1 00:00:09,990 --> 00:00:12,170 last time remember we were talking about 2 00:00:12,170 --> 00:00:12,180 last time remember we were talking about 3 00:00:12,180 --> 00:00:20,540 last time remember we were talking about the intermolecular forces and again we 4 00:00:20,540 --> 00:00:20,550 the intermolecular forces and again we 5 00:00:20,550 --> 00:00:22,370 the intermolecular forces and again we said that these intermolecular forces 6 00:00:22,370 --> 00:00:22,380 said that these intermolecular forces 7 00:00:22,380 --> 00:00:27,650 said that these intermolecular forces are much weaker than chemical bond 8 00:00:27,650 --> 00:00:27,660 are much weaker than chemical bond 9 00:00:27,660 --> 00:00:33,619 are much weaker than chemical bond energies chemical bonds but they 10 00:00:33,619 --> 00:00:33,629 energies chemical bonds but they 11 00:00:33,629 --> 00:00:36,770 energies chemical bonds but they determine very important physical 12 00:00:36,770 --> 00:00:36,780 determine very important physical 13 00:00:36,780 --> 00:00:40,970 determine very important physical properties of the compound particularly 14 00:00:40,970 --> 00:00:40,980 properties of the compound particularly 15 00:00:40,980 --> 00:00:44,240 properties of the compound particularly the liquids and what kind of physical 16 00:00:44,240 --> 00:00:44,250 the liquids and what kind of physical 17 00:00:44,250 --> 00:00:46,759 the liquids and what kind of physical properties for the liquids particularly 18 00:00:46,759 --> 00:00:46,769 properties for the liquids particularly 19 00:00:46,769 --> 00:00:49,340 properties for the liquids particularly Mountain points for the solids again 20 00:00:49,340 --> 00:00:49,350 Mountain points for the solids again 21 00:00:49,350 --> 00:00:52,549 Mountain points for the solids again melting points boiling point and for the 22 00:00:52,549 --> 00:00:52,559 melting points boiling point and for the 23 00:00:52,559 --> 00:00:57,410 melting points boiling point and for the liquid vapour pressure viscosity surface 24 00:00:57,410 --> 00:00:57,420 liquid vapour pressure viscosity surface 25 00:00:57,420 --> 00:01:00,759 liquid vapour pressure viscosity surface tension and all of these are simply 26 00:01:00,759 --> 00:01:00,769 tension and all of these are simply 27 00:01:00,769 --> 00:01:04,009 tension and all of these are simply determined by the intermolecular forces 28 00:01:04,009 --> 00:01:04,019 determined by the intermolecular forces 29 00:01:04,019 --> 00:01:09,260 determined by the intermolecular forces and let's go through again the types of 30 00:01:09,260 --> 00:01:09,270 and let's go through again the types of 31 00:01:09,270 --> 00:01:12,260 and let's go through again the types of intermolecular forces one is the 32 00:01:12,260 --> 00:01:12,270 intermolecular forces one is the 33 00:01:12,270 --> 00:01:15,499 intermolecular forces one is the dispersion forces in fact this is also 34 00:01:15,499 --> 00:01:15,509 dispersion forces in fact this is also 35 00:01:15,509 --> 00:01:17,990 dispersion forces in fact this is also called London forces dipole-dipole 36 00:01:17,990 --> 00:01:18,000 called London forces dipole-dipole 37 00:01:18,000 --> 00:01:22,639 called London forces dipole-dipole forces and hydrogen bonding and ion 38 00:01:22,639 --> 00:01:22,649 forces and hydrogen bonding and ion 39 00:01:22,649 --> 00:01:34,280 forces and hydrogen bonding and ion dipole forces 40 00:01:34,280 --> 00:01:34,290 41 00:01:34,290 --> 00:01:37,460 now we talked about this dispersion 42 00:01:37,460 --> 00:01:37,470 now we talked about this dispersion 43 00:01:37,470 --> 00:01:42,590 now we talked about this dispersion forces and dispersion forces we said are 44 00:01:42,590 --> 00:01:42,600 forces and dispersion forces we said are 45 00:01:42,600 --> 00:01:46,460 forces and dispersion forces we said are found almost in all substances and it 46 00:01:46,460 --> 00:01:46,470 found almost in all substances and it 47 00:01:46,470 --> 00:01:48,770 found almost in all substances and it operates between all kind of molecules 48 00:01:48,770 --> 00:01:48,780 operates between all kind of molecules 49 00:01:48,780 --> 00:01:53,330 operates between all kind of molecules and dipole-dipole forces are only 50 00:01:53,330 --> 00:01:53,340 and dipole-dipole forces are only 51 00:01:53,340 --> 00:01:57,400 and dipole-dipole forces are only present between two polar molecules and 52 00:01:57,400 --> 00:01:57,410 present between two polar molecules and 53 00:01:57,410 --> 00:02:00,580 present between two polar molecules and hydrogen bonding is a special type of 54 00:02:00,580 --> 00:02:00,590 hydrogen bonding is a special type of 55 00:02:00,590 --> 00:02:03,740 hydrogen bonding is a special type of force attraction force between the 56 00:02:03,740 --> 00:02:03,750 force attraction force between the 57 00:02:03,750 --> 00:02:06,469 force attraction force between the molecules with where you should have a 58 00:02:06,469 --> 00:02:06,479 molecules with where you should have a 59 00:02:06,479 --> 00:02:08,480 molecules with where you should have a hydrogen bonded to a most 60 00:02:08,480 --> 00:02:08,490 hydrogen bonded to a most 61 00:02:08,490 --> 00:02:11,780 hydrogen bonded to a most electronegative element those are three 62 00:02:11,780 --> 00:02:11,790 electronegative element those are three 63 00:02:11,790 --> 00:02:14,000 electronegative element those are three actually fluorine oxygen and nitrogen 64 00:02:14,000 --> 00:02:14,010 actually fluorine oxygen and nitrogen 65 00:02:14,010 --> 00:02:17,750 actually fluorine oxygen and nitrogen and you should also have the lone pair 66 00:02:17,750 --> 00:02:17,760 and you should also have the lone pair 67 00:02:17,760 --> 00:02:20,420 and you should also have the lone pair electrons on these most electronegative 68 00:02:20,420 --> 00:02:20,430 electrons on these most electronegative 69 00:02:20,430 --> 00:02:23,690 electrons on these most electronegative elements and we try to explain those 70 00:02:23,690 --> 00:02:23,700 elements and we try to explain those 71 00:02:23,700 --> 00:02:28,070 elements and we try to explain those last time remember and the ion dipole 72 00:02:28,070 --> 00:02:28,080 last time remember and the ion dipole 73 00:02:28,080 --> 00:02:31,810 last time remember and the ion dipole forces are the forces between an ion and 74 00:02:31,810 --> 00:02:31,820 forces are the forces between an ion and 75 00:02:31,820 --> 00:02:35,180 forces are the forces between an ion and a dipole and this is usually present in 76 00:02:35,180 --> 00:02:35,190 a dipole and this is usually present in 77 00:02:35,190 --> 00:02:38,000 a dipole and this is usually present in solutions because you can have the ions 78 00:02:38,000 --> 00:02:38,010 solutions because you can have the ions 79 00:02:38,010 --> 00:02:41,270 solutions because you can have the ions in solutions and you also have dipole 80 00:02:41,270 --> 00:02:41,280 in solutions and you also have dipole 81 00:02:41,280 --> 00:02:43,640 in solutions and you also have dipole molecules in solutions and when you have 82 00:02:43,640 --> 00:02:43,650 molecules in solutions and when you have 83 00:02:43,650 --> 00:02:48,040 molecules in solutions and when you have iron ions in solutions and the dipole 84 00:02:48,040 --> 00:02:48,050 iron ions in solutions and the dipole 85 00:02:48,050 --> 00:02:50,810 iron ions in solutions and the dipole polar molecules actually in solutions 86 00:02:50,810 --> 00:02:50,820 polar molecules actually in solutions 87 00:02:50,820 --> 00:02:53,590 polar molecules actually in solutions then you will have ion dipole 88 00:02:53,590 --> 00:02:53,600 then you will have ion dipole 89 00:02:53,600 --> 00:02:58,070 then you will have ion dipole attractions let's go quickly again we 90 00:02:58,070 --> 00:02:58,080 attractions let's go quickly again we 91 00:02:58,080 --> 00:03:00,949 attractions let's go quickly again we explain how dispersion forces or London 92 00:03:00,949 --> 00:03:00,959 explain how dispersion forces or London 93 00:03:00,959 --> 00:03:03,190 explain how dispersion forces or London forces operates between molecules 94 00:03:03,190 --> 00:03:03,200 forces operates between molecules 95 00:03:03,200 --> 00:03:06,340 forces operates between molecules particularly important for nonpolar 96 00:03:06,340 --> 00:03:06,350 particularly important for nonpolar 97 00:03:06,350 --> 00:03:08,270 particularly important for nonpolar molecules if you have a non-polar 98 00:03:08,270 --> 00:03:08,280 molecules if you have a non-polar 99 00:03:08,280 --> 00:03:10,390 molecules if you have a non-polar molecule or nonpolar antem the 100 00:03:10,390 --> 00:03:10,400 molecule or nonpolar antem the 101 00:03:10,400 --> 00:03:13,600 molecule or nonpolar antem the attraction force is only actually 102 00:03:13,600 --> 00:03:13,610 attraction force is only actually 103 00:03:13,610 --> 00:03:17,660 attraction force is only actually dispersion forces between them and again 104 00:03:17,660 --> 00:03:17,670 dispersion forces between them and again 105 00:03:17,670 --> 00:03:21,110 dispersion forces between them and again dispersion forces we said he depends on 106 00:03:21,110 --> 00:03:21,120 dispersion forces we said he depends on 107 00:03:21,120 --> 00:03:23,420 dispersion forces we said he depends on the number of electrons in the atom or 108 00:03:23,420 --> 00:03:23,430 the number of electrons in the atom or 109 00:03:23,430 --> 00:03:25,880 the number of electrons in the atom or the molecule size of the atom and shape 110 00:03:25,880 --> 00:03:25,890 the molecule size of the atom and shape 111 00:03:25,890 --> 00:03:29,930 the molecule size of the atom and shape of the atom again the more electrons you 112 00:03:29,930 --> 00:03:29,940 of the atom again the more electrons you 113 00:03:29,940 --> 00:03:31,790 of the atom again the more electrons you have in the atom or the molecule that 114 00:03:31,790 --> 00:03:31,800 have in the atom or the molecule that 115 00:03:31,800 --> 00:03:35,810 have in the atom or the molecule that means the greater dispersion forces will 116 00:03:35,810 --> 00:03:35,820 means the greater dispersion forces will 117 00:03:35,820 --> 00:03:38,390 means the greater dispersion forces will exist in that compound and the shape 118 00:03:38,390 --> 00:03:38,400 exist in that compound and the shape 119 00:03:38,400 --> 00:03:41,540 exist in that compound and the shape also affects the dispersion forces too 120 00:03:41,540 --> 00:03:41,550 also affects the dispersion forces too 121 00:03:41,550 --> 00:03:47,000 also affects the dispersion forces too and this is again polarizability also 122 00:03:47,000 --> 00:03:47,010 and this is again polarizability also 123 00:03:47,010 --> 00:03:48,070 and this is again polarizability also determines the 124 00:03:48,070 --> 00:03:48,080 determines the 125 00:03:48,080 --> 00:03:50,330 determines the dispersion forces between nonpolar 126 00:03:50,330 --> 00:03:50,340 dispersion forces between nonpolar 127 00:03:50,340 --> 00:03:53,180 dispersion forces between nonpolar molecules if it is easy to polarize a 128 00:03:53,180 --> 00:03:53,190 molecules if it is easy to polarize a 129 00:03:53,190 --> 00:03:56,360 molecules if it is easy to polarize a molecule that means move the electron to 130 00:03:56,360 --> 00:03:56,370 molecule that means move the electron to 131 00:03:56,370 --> 00:03:59,660 molecule that means move the electron to more one side and have Delta positive 132 00:03:59,660 --> 00:03:59,670 more one side and have Delta positive 133 00:03:59,670 --> 00:04:01,520 more one side and have Delta positive and Delta negative side of the molecule 134 00:04:01,520 --> 00:04:01,530 and Delta negative side of the molecule 135 00:04:01,530 --> 00:04:03,680 and Delta negative side of the molecule or the atom in that case you will have 136 00:04:03,680 --> 00:04:03,690 or the atom in that case you will have 137 00:04:03,690 --> 00:04:09,920 or the atom in that case you will have larger dispersion forces actually now 138 00:04:09,920 --> 00:04:09,930 larger dispersion forces actually now 139 00:04:09,930 --> 00:04:13,370 larger dispersion forces actually now again dipole-dipole interactions are 140 00:04:13,370 --> 00:04:13,380 again dipole-dipole interactions are 141 00:04:13,380 --> 00:04:16,490 again dipole-dipole interactions are only present between two polar molecules 142 00:04:16,490 --> 00:04:16,500 only present between two polar molecules 143 00:04:16,500 --> 00:04:19,070 only present between two polar molecules and again positive side of molecule 144 00:04:19,070 --> 00:04:19,080 and again positive side of molecule 145 00:04:19,080 --> 00:04:21,260 and again positive side of molecule attracts the negative side and this is 146 00:04:21,260 --> 00:04:21,270 attracts the negative side and this is 147 00:04:21,270 --> 00:04:24,800 attracts the negative side and this is the dipole-dipole interactions or 148 00:04:24,800 --> 00:04:24,810 the dipole-dipole interactions or 149 00:04:24,810 --> 00:04:26,990 the dipole-dipole interactions or dipole-dipole forces again as 150 00:04:26,990 --> 00:04:27,000 dipole-dipole forces again as 151 00:04:27,000 --> 00:04:30,140 dipole-dipole forces again as intermolecular forces now as the gain 152 00:04:30,140 --> 00:04:30,150 intermolecular forces now as the gain 153 00:04:30,150 --> 00:04:31,610 intermolecular forces now as the gain last time we said dipole-dipole 154 00:04:31,610 --> 00:04:31,620 last time we said dipole-dipole 155 00:04:31,620 --> 00:04:35,180 last time we said dipole-dipole interactions is simply determined by the 156 00:04:35,180 --> 00:04:35,190 interactions is simply determined by the 157 00:04:35,190 --> 00:04:38,420 interactions is simply determined by the dipole moment of the molecule the higher 158 00:04:38,420 --> 00:04:38,430 dipole moment of the molecule the higher 159 00:04:38,430 --> 00:04:40,310 dipole moment of the molecule the higher the dipole moment the stronger will be 160 00:04:40,310 --> 00:04:40,320 the dipole moment the stronger will be 161 00:04:40,320 --> 00:04:43,430 the dipole moment the stronger will be the dipole dipole forces in that 162 00:04:43,430 --> 00:04:43,440 the dipole dipole forces in that 163 00:04:43,440 --> 00:04:48,380 the dipole dipole forces in that molecule and depending on those forces 164 00:04:48,380 --> 00:04:48,390 molecule and depending on those forces 165 00:04:48,390 --> 00:04:51,020 molecule and depending on those forces again dipole moments and I pulled up all 166 00:04:51,020 --> 00:04:51,030 again dipole moments and I pulled up all 167 00:04:51,030 --> 00:04:53,180 again dipole moments and I pulled up all interactions the boiling point of the 168 00:04:53,180 --> 00:04:53,190 interactions the boiling point of the 169 00:04:53,190 --> 00:04:56,360 interactions the boiling point of the compounds changes as we will see later 170 00:04:56,360 --> 00:04:56,370 compounds changes as we will see later 171 00:04:56,370 --> 00:05:00,560 compounds changes as we will see later more the higher the attraction between 172 00:05:00,560 --> 00:05:00,570 more the higher the attraction between 173 00:05:00,570 --> 00:05:03,020 more the higher the attraction between the liquid molecules the higher will be 174 00:05:03,020 --> 00:05:03,030 the liquid molecules the higher will be 175 00:05:03,030 --> 00:05:07,940 the liquid molecules the higher will be the boiling point of the molecule now 176 00:05:07,940 --> 00:05:07,950 the boiling point of the molecule now 177 00:05:07,950 --> 00:05:10,430 the boiling point of the molecule now which have a greater effect this is 178 00:05:10,430 --> 00:05:10,440 which have a greater effect this is 179 00:05:10,440 --> 00:05:13,659 which have a greater effect this is again when you have all of these 180 00:05:13,659 --> 00:05:13,669 again when you have all of these 181 00:05:13,669 --> 00:05:16,370 again when you have all of these intermolecular forces dispersion forces 182 00:05:16,370 --> 00:05:16,380 intermolecular forces dispersion forces 183 00:05:16,380 --> 00:05:19,030 intermolecular forces dispersion forces dipole-dipole hydrogen bonding which is 184 00:05:19,030 --> 00:05:19,040 dipole-dipole hydrogen bonding which is 185 00:05:19,040 --> 00:05:21,440 dipole-dipole hydrogen bonding which is more important which is dominant which 186 00:05:21,440 --> 00:05:21,450 more important which is dominant which 187 00:05:21,450 --> 00:05:26,750 more important which is dominant which has more effect now if the molecules it 188 00:05:26,750 --> 00:05:26,760 has more effect now if the molecules it 189 00:05:26,760 --> 00:05:28,880 has more effect now if the molecules it says are comparable size and shape 190 00:05:28,880 --> 00:05:28,890 says are comparable size and shape 191 00:05:28,890 --> 00:05:31,190 says are comparable size and shape dipole-dipole interactions were likely 192 00:05:31,190 --> 00:05:31,200 dipole-dipole interactions were likely 193 00:05:31,200 --> 00:05:33,080 dipole-dipole interactions were likely to be dominated force that means if you 194 00:05:33,080 --> 00:05:33,090 to be dominated force that means if you 195 00:05:33,090 --> 00:05:35,500 to be dominated force that means if you have two molecules and you try to 196 00:05:35,500 --> 00:05:35,510 have two molecules and you try to 197 00:05:35,510 --> 00:05:38,090 have two molecules and you try to compare the intermolecular forces 198 00:05:38,090 --> 00:05:38,100 compare the intermolecular forces 199 00:05:38,100 --> 00:05:43,580 compare the intermolecular forces between those two molecules and if the 200 00:05:43,580 --> 00:05:43,590 between those two molecules and if the 201 00:05:43,590 --> 00:05:46,730 between those two molecules and if the molecules have about the same molecular 202 00:05:46,730 --> 00:05:46,740 molecules have about the same molecular 203 00:05:46,740 --> 00:05:49,480 molecules have about the same molecular weight that means about the same size 204 00:05:49,480 --> 00:05:49,490 weight that means about the same size 205 00:05:49,490 --> 00:05:52,190 weight that means about the same size then you look at whether the molecules 206 00:05:52,190 --> 00:05:52,200 then you look at whether the molecules 207 00:05:52,200 --> 00:05:55,610 then you look at whether the molecules are polar molecules if one is polar the 208 00:05:55,610 --> 00:05:55,620 are polar molecules if one is polar the 209 00:05:55,620 --> 00:05:57,350 are polar molecules if one is polar the other one is nonpolar then the 210 00:05:57,350 --> 00:05:57,360 other one is nonpolar then the 211 00:05:57,360 --> 00:05:59,360 other one is nonpolar then the intermolecular forces in the polar 212 00:05:59,360 --> 00:05:59,370 intermolecular forces in the polar 213 00:05:59,370 --> 00:06:01,279 intermolecular forces in the polar molecule will be greater than 214 00:06:01,279 --> 00:06:01,289 molecule will be greater than 215 00:06:01,289 --> 00:06:03,409 molecule will be greater than nonpolar molecules because you assumed 216 00:06:03,409 --> 00:06:03,419 nonpolar molecules because you assumed 217 00:06:03,419 --> 00:06:05,779 nonpolar molecules because you assumed there that the London dispersion forces 218 00:06:05,779 --> 00:06:05,789 there that the London dispersion forces 219 00:06:05,789 --> 00:06:08,779 there that the London dispersion forces in fact will be the same because they 220 00:06:08,779 --> 00:06:08,789 in fact will be the same because they 221 00:06:08,789 --> 00:06:11,179 in fact will be the same because they have the same molecular weight the same 222 00:06:11,179 --> 00:06:11,189 have the same molecular weight the same 223 00:06:11,189 --> 00:06:13,369 have the same molecular weight the same size about the same number of electrons 224 00:06:13,369 --> 00:06:13,379 size about the same number of electrons 225 00:06:13,379 --> 00:06:16,040 size about the same number of electrons probably now if one molecule is much 226 00:06:16,040 --> 00:06:16,050 probably now if one molecule is much 227 00:06:16,050 --> 00:06:18,649 probably now if one molecule is much larger than the other dispersion forces 228 00:06:18,649 --> 00:06:18,659 larger than the other dispersion forces 229 00:06:18,659 --> 00:06:20,299 larger than the other dispersion forces will determine its its physical 230 00:06:20,299 --> 00:06:20,309 will determine its its physical 231 00:06:20,309 --> 00:06:22,489 will determine its its physical properties particularly when we have 232 00:06:22,489 --> 00:06:22,499 properties particularly when we have 233 00:06:22,499 --> 00:06:25,579 properties particularly when we have very large molecules dispersion forces 234 00:06:25,579 --> 00:06:25,589 very large molecules dispersion forces 235 00:06:25,589 --> 00:06:29,089 very large molecules dispersion forces becomes the dominant force determined in 236 00:06:29,089 --> 00:06:29,099 becomes the dominant force determined in 237 00:06:29,099 --> 00:06:31,010 becomes the dominant force determined in the physical properties of the compound 238 00:06:31,010 --> 00:06:31,020 the physical properties of the compound 239 00:06:31,020 --> 00:06:35,049 the physical properties of the compound now again this simply shows how the 240 00:06:35,049 --> 00:06:35,059 now again this simply shows how the 241 00:06:35,059 --> 00:06:38,629 now again this simply shows how the hydrogen bonding changes the physical 242 00:06:38,629 --> 00:06:38,639 hydrogen bonding changes the physical 243 00:06:38,639 --> 00:06:41,420 hydrogen bonding changes the physical property of the liquids in fact in this 244 00:06:41,420 --> 00:06:41,430 property of the liquids in fact in this 245 00:06:41,430 --> 00:06:44,869 property of the liquids in fact in this case the boiling point of the water 246 00:06:44,869 --> 00:06:44,879 case the boiling point of the water 247 00:06:44,879 --> 00:06:47,239 case the boiling point of the water molecule hydrogen fluoride and ammonia 248 00:06:47,239 --> 00:06:47,249 molecule hydrogen fluoride and ammonia 249 00:06:47,249 --> 00:06:50,149 molecule hydrogen fluoride and ammonia is much higher than what we expect 250 00:06:50,149 --> 00:06:50,159 is much higher than what we expect 251 00:06:50,159 --> 00:06:52,909 is much higher than what we expect actually comparing with the others in 252 00:06:52,909 --> 00:06:52,919 actually comparing with the others in 253 00:06:52,919 --> 00:06:55,399 actually comparing with the others in the same group and the reason is because 254 00:06:55,399 --> 00:06:55,409 the same group and the reason is because 255 00:06:55,409 --> 00:06:58,129 the same group and the reason is because they have hydrogen bonding in fact 256 00:06:58,129 --> 00:06:58,139 they have hydrogen bonding in fact 257 00:06:58,139 --> 00:07:00,320 they have hydrogen bonding in fact hydrogen bonding is possible between two 258 00:07:00,320 --> 00:07:00,330 hydrogen bonding is possible between two 259 00:07:00,330 --> 00:07:02,119 hydrogen bonding is possible between two water molecules or two hydrogen fluoride 260 00:07:02,119 --> 00:07:02,129 water molecules or two hydrogen fluoride 261 00:07:02,129 --> 00:07:05,299 water molecules or two hydrogen fluoride and two ammonia that simply makes the 262 00:07:05,299 --> 00:07:05,309 and two ammonia that simply makes the 263 00:07:05,309 --> 00:07:07,790 and two ammonia that simply makes the boiling point of these compounds of 264 00:07:07,790 --> 00:07:07,800 boiling point of these compounds of 265 00:07:07,800 --> 00:07:10,999 boiling point of these compounds of these liquids in fact much greater than 266 00:07:10,999 --> 00:07:11,009 these liquids in fact much greater than 267 00:07:11,009 --> 00:07:15,199 these liquids in fact much greater than what we expect this is again explains 268 00:07:15,199 --> 00:07:15,209 what we expect this is again explains 269 00:07:15,209 --> 00:07:17,089 what we expect this is again explains how the hydrogen bonding we talked about 270 00:07:17,089 --> 00:07:17,099 how the hydrogen bonding we talked about 271 00:07:17,099 --> 00:07:21,139 how the hydrogen bonding we talked about that last time now this is the ion 272 00:07:21,139 --> 00:07:21,149 that last time now this is the ion 273 00:07:21,149 --> 00:07:25,089 that last time now this is the ion dipole interactions again when you have 274 00:07:25,089 --> 00:07:25,099 dipole interactions again when you have 275 00:07:25,099 --> 00:07:29,119 dipole interactions again when you have for example sodium chloride this is 276 00:07:29,119 --> 00:07:29,129 for example sodium chloride this is 277 00:07:29,129 --> 00:07:31,879 for example sodium chloride this is solid crystalline solids and you 278 00:07:31,879 --> 00:07:31,889 solid crystalline solids and you 279 00:07:31,889 --> 00:07:35,839 solid crystalline solids and you dissolve it in water simply in water 280 00:07:35,839 --> 00:07:35,849 dissolve it in water simply in water 281 00:07:35,849 --> 00:07:39,199 dissolve it in water simply in water then we write it again as followers it 282 00:07:39,199 --> 00:07:39,209 then we write it again as followers it 283 00:07:39,209 --> 00:07:43,459 then we write it again as followers it dissolves in water we have sodium plus 284 00:07:43,459 --> 00:07:43,469 dissolves in water we have sodium plus 285 00:07:43,469 --> 00:07:48,469 dissolves in water we have sodium plus ions and plus chloride minus ions in 286 00:07:48,469 --> 00:07:48,479 ions and plus chloride minus ions in 287 00:07:48,479 --> 00:07:52,219 ions and plus chloride minus ions in aqueous solutions this 8 2 simply says 288 00:07:52,219 --> 00:07:52,229 aqueous solutions this 8 2 simply says 289 00:07:52,229 --> 00:07:54,350 aqueous solutions this 8 2 simply says that it is water the solvent in this 290 00:07:54,350 --> 00:07:54,360 that it is water the solvent in this 291 00:07:54,360 --> 00:07:57,799 that it is water the solvent in this case is water now these simply means 292 00:07:57,799 --> 00:07:57,809 case is water now these simply means 293 00:07:57,809 --> 00:08:01,969 case is water now these simply means this the equated sodium plus ion is the 294 00:08:01,969 --> 00:08:01,979 this the equated sodium plus ion is the 295 00:08:01,979 --> 00:08:04,579 this the equated sodium plus ion is the water molecules these are their h2o 296 00:08:04,579 --> 00:08:04,589 water molecules these are their h2o 297 00:08:04,589 --> 00:08:08,540 water molecules these are their h2o water molecules over here h2o 298 00:08:08,540 --> 00:08:08,550 water molecules over here h2o 299 00:08:08,550 --> 00:08:13,730 water molecules over here h2o and another h2o like this and remember 300 00:08:13,730 --> 00:08:13,740 and another h2o like this and remember 301 00:08:13,740 --> 00:08:15,140 and another h2o like this and remember the water molecule 302 00:08:15,140 --> 00:08:15,150 the water molecule 303 00:08:15,150 --> 00:08:18,080 the water molecule are polar molecules what is that means 304 00:08:18,080 --> 00:08:18,090 are polar molecules what is that means 305 00:08:18,090 --> 00:08:20,750 are polar molecules what is that means one side is positive the other side is 306 00:08:20,750 --> 00:08:20,760 one side is positive the other side is 307 00:08:20,760 --> 00:08:24,260 one side is positive the other side is negative so when you have sodium ion in 308 00:08:24,260 --> 00:08:24,270 negative so when you have sodium ion in 309 00:08:24,270 --> 00:08:26,390 negative so when you have sodium ion in solution positively charged sodium ion 310 00:08:26,390 --> 00:08:26,400 solution positively charged sodium ion 311 00:08:26,400 --> 00:08:29,540 solution positively charged sodium ion in solutions then the Delta minus side 312 00:08:29,540 --> 00:08:29,550 in solutions then the Delta minus side 313 00:08:29,550 --> 00:08:33,320 in solutions then the Delta minus side of the water molecule will simply 314 00:08:33,320 --> 00:08:33,330 of the water molecule will simply 315 00:08:33,330 --> 00:08:40,159 of the water molecule will simply interact with the sodium plus cation in 316 00:08:40,159 --> 00:08:40,169 interact with the sodium plus cation in 317 00:08:40,169 --> 00:08:47,630 interact with the sodium plus cation in fact and we have ion dipole interactions 318 00:08:47,630 --> 00:08:47,640 fact and we have ion dipole interactions 319 00:08:47,640 --> 00:08:50,120 fact and we have ion dipole interactions actually right so let's say this is 320 00:08:50,120 --> 00:08:50,130 actually right so let's say this is 321 00:08:50,130 --> 00:08:53,600 actually right so let's say this is Delta minus Delta plus Delta minus and 322 00:08:53,600 --> 00:08:53,610 Delta minus Delta plus Delta minus and 323 00:08:53,610 --> 00:08:56,180 Delta minus Delta plus Delta minus and Delta plus remember the water molecule 324 00:08:56,180 --> 00:08:56,190 Delta plus remember the water molecule 325 00:08:56,190 --> 00:08:58,370 Delta plus remember the water molecule one side a little bit positively a 326 00:08:58,370 --> 00:08:58,380 one side a little bit positively a 327 00:08:58,380 --> 00:09:00,650 one side a little bit positively a little bit negative so when you have 328 00:09:00,650 --> 00:09:00,660 little bit negative so when you have 329 00:09:00,660 --> 00:09:04,760 little bit negative so when you have actually iron in water and water 330 00:09:04,760 --> 00:09:04,770 actually iron in water and water 331 00:09:04,770 --> 00:09:07,190 actually iron in water and water molecules will surround this ion and 332 00:09:07,190 --> 00:09:07,200 molecules will surround this ion and 333 00:09:07,200 --> 00:09:09,079 molecules will surround this ion and there's going to be attraction between 334 00:09:09,079 --> 00:09:09,089 there's going to be attraction between 335 00:09:09,089 --> 00:09:12,950 there's going to be attraction between that ion and the water molecule which is 336 00:09:12,950 --> 00:09:12,960 that ion and the water molecule which is 337 00:09:12,960 --> 00:09:15,920 that ion and the water molecule which is a polar molecule and that's why we call 338 00:09:15,920 --> 00:09:15,930 a polar molecule and that's why we call 339 00:09:15,930 --> 00:09:18,910 a polar molecule and that's why we call that ion dipole interactions actually 340 00:09:18,910 --> 00:09:18,920 that ion dipole interactions actually 341 00:09:18,920 --> 00:09:22,490 that ion dipole interactions actually this ion dipole interactions determines 342 00:09:22,490 --> 00:09:22,500 this ion dipole interactions determines 343 00:09:22,500 --> 00:09:24,980 this ion dipole interactions determines the solubility affects the solubility of 344 00:09:24,980 --> 00:09:24,990 the solubility affects the solubility of 345 00:09:24,990 --> 00:09:29,150 the solubility affects the solubility of the solid that dissolve in water 346 00:09:29,150 --> 00:09:29,160 the solid that dissolve in water 347 00:09:29,160 --> 00:09:33,010 the solid that dissolve in water if this attractions in fact myung dipole 348 00:09:33,010 --> 00:09:33,020 if this attractions in fact myung dipole 349 00:09:33,020 --> 00:09:37,190 if this attractions in fact myung dipole attractions is not present then the 350 00:09:37,190 --> 00:09:37,200 attractions is not present then the 351 00:09:37,200 --> 00:09:40,760 attractions is not present then the sodium chloride will not dissolve in 352 00:09:40,760 --> 00:09:40,770 sodium chloride will not dissolve in 353 00:09:40,770 --> 00:09:41,960 sodium chloride will not dissolve in water 354 00:09:41,960 --> 00:09:41,970 water 355 00:09:41,970 --> 00:09:45,500 water Mata's alva and usually the ionic 356 00:09:45,500 --> 00:09:45,510 Mata's alva and usually the ionic 357 00:09:45,510 --> 00:09:48,350 Mata's alva and usually the ionic compounds dissolve in polar solvents 358 00:09:48,350 --> 00:09:48,360 compounds dissolve in polar solvents 359 00:09:48,360 --> 00:09:50,769 compounds dissolve in polar solvents such as water and the reason is because 360 00:09:50,769 --> 00:09:50,779 such as water and the reason is because 361 00:09:50,779 --> 00:09:54,579 such as water and the reason is because ion dipole interactions is very strong 362 00:09:54,579 --> 00:09:54,589 ion dipole interactions is very strong 363 00:09:54,589 --> 00:09:58,190 ion dipole interactions is very strong interactions as a matter of fact okay 364 00:09:58,190 --> 00:09:58,200 interactions as a matter of fact okay 365 00:09:58,200 --> 00:10:00,440 interactions as a matter of fact okay now this is again summarizes 366 00:10:00,440 --> 00:10:00,450 now this is again summarizes 367 00:10:00,450 --> 00:10:03,050 now this is again summarizes intermolecular forces we should probably 368 00:10:03,050 --> 00:10:03,060 intermolecular forces we should probably 369 00:10:03,060 --> 00:10:04,699 intermolecular forces we should probably look at here 370 00:10:04,699 --> 00:10:04,709 look at here 371 00:10:04,709 --> 00:10:08,690 look at here dispersion forces only nonpolar 372 00:10:08,690 --> 00:10:08,700 dispersion forces only nonpolar 373 00:10:08,700 --> 00:10:10,790 dispersion forces only nonpolar molecules again if you have a non-polar 374 00:10:10,790 --> 00:10:10,800 molecules again if you have a non-polar 375 00:10:10,800 --> 00:10:14,350 molecules again if you have a non-polar molecule such as methane and bromine 376 00:10:14,350 --> 00:10:14,360 molecule such as methane and bromine 377 00:10:14,360 --> 00:10:18,620 molecule such as methane and bromine molecules then the only intermolecular 378 00:10:18,620 --> 00:10:18,630 molecules then the only intermolecular 379 00:10:18,630 --> 00:10:21,740 molecules then the only intermolecular forces that operates in that compound 380 00:10:21,740 --> 00:10:21,750 forces that operates in that compound 381 00:10:21,750 --> 00:10:23,480 forces that operates in that compound those compounds will be dispersion 382 00:10:23,480 --> 00:10:23,490 those compounds will be dispersion 383 00:10:23,490 --> 00:10:25,530 those compounds will be dispersion forces and the 384 00:10:25,530 --> 00:10:25,540 forces and the 385 00:10:25,540 --> 00:10:29,040 forces and the dispersion forces again changes between 386 00:10:29,040 --> 00:10:29,050 dispersion forces again changes between 387 00:10:29,050 --> 00:10:33,720 dispersion forces again changes between 0.1 to 30 kilojoules per mole 30 388 00:10:33,720 --> 00:10:33,730 0.1 to 30 kilojoules per mole 30 389 00:10:33,730 --> 00:10:36,240 0.1 to 30 kilojoules per mole 30 kilojoules per mole again remember the 390 00:10:36,240 --> 00:10:36,250 kilojoules per mole again remember the 391 00:10:36,250 --> 00:10:38,639 kilojoules per mole again remember the chemical bond the weakest bond 392 00:10:38,639 --> 00:10:38,649 chemical bond the weakest bond 393 00:10:38,649 --> 00:10:40,530 chemical bond the weakest bond corresponds to about one hundred and 394 00:10:40,530 --> 00:10:40,540 corresponds to about one hundred and 395 00:10:40,540 --> 00:10:43,079 corresponds to about one hundred and hundred and fifty kilojoules per mole so 396 00:10:43,079 --> 00:10:43,089 hundred and fifty kilojoules per mole so 397 00:10:43,089 --> 00:10:45,269 hundred and fifty kilojoules per mole so what does that mean that means that the 398 00:10:45,269 --> 00:10:45,279 what does that mean that means that the 399 00:10:45,279 --> 00:10:47,579 what does that mean that means that the dispersion forces dispersion are much 400 00:10:47,579 --> 00:10:47,589 dispersion forces dispersion are much 401 00:10:47,589 --> 00:10:50,519 dispersion forces dispersion are much weaker than chemical bond forces 402 00:10:50,519 --> 00:10:50,529 weaker than chemical bond forces 403 00:10:50,529 --> 00:10:54,050 weaker than chemical bond forces actually now if you have a dipole-dipole 404 00:10:54,050 --> 00:10:54,060 actually now if you have a dipole-dipole 405 00:10:54,060 --> 00:10:57,150 actually now if you have a dipole-dipole molecule again polar molecules then we 406 00:10:57,150 --> 00:10:57,160 molecule again polar molecules then we 407 00:10:57,160 --> 00:10:59,579 molecule again polar molecules then we have the dipole dipole forces will 408 00:10:59,579 --> 00:10:59,589 have the dipole dipole forces will 409 00:10:59,589 --> 00:11:03,449 have the dipole dipole forces will operate now remember even input between 410 00:11:03,449 --> 00:11:03,459 operate now remember even input between 411 00:11:03,459 --> 00:11:06,360 operate now remember even input between two polar molecules dispersion forces 412 00:11:06,360 --> 00:11:06,370 two polar molecules dispersion forces 413 00:11:06,370 --> 00:11:09,720 two polar molecules dispersion forces also present their dispersion forces 414 00:11:09,720 --> 00:11:09,730 also present their dispersion forces 415 00:11:09,730 --> 00:11:12,590 also present their dispersion forces always there but when you have simply 416 00:11:12,590 --> 00:11:12,600 always there but when you have simply 417 00:11:12,600 --> 00:11:15,530 always there but when you have simply polar molecules dipole dipole 418 00:11:15,530 --> 00:11:15,540 polar molecules dipole dipole 419 00:11:15,540 --> 00:11:18,840 polar molecules dipole dipole attractions then the the dispersion 420 00:11:18,840 --> 00:11:18,850 attractions then the the dispersion 421 00:11:18,850 --> 00:11:21,329 attractions then the the dispersion forces is not that important in that 422 00:11:21,329 --> 00:11:21,339 forces is not that important in that 423 00:11:21,339 --> 00:11:23,970 forces is not that important in that case now again between the polar 424 00:11:23,970 --> 00:11:23,980 case now again between the polar 425 00:11:23,980 --> 00:11:27,120 case now again between the polar molecules as over here the energies of 426 00:11:27,120 --> 00:11:27,130 molecules as over here the energies of 427 00:11:27,130 --> 00:11:30,199 molecules as over here the energies of the attraction corresponds to about 428 00:11:30,199 --> 00:11:30,209 the attraction corresponds to about 429 00:11:30,209 --> 00:11:33,569 the attraction corresponds to about between 2 and 15 kilojoules per mole 430 00:11:33,569 --> 00:11:33,579 between 2 and 15 kilojoules per mole 431 00:11:33,579 --> 00:11:35,610 between 2 and 15 kilojoules per mole again you see that the range of 432 00:11:35,610 --> 00:11:35,620 again you see that the range of 433 00:11:35,620 --> 00:11:38,750 again you see that the range of dispersion forces is bigger than the 434 00:11:38,750 --> 00:11:38,760 dispersion forces is bigger than the 435 00:11:38,760 --> 00:11:43,370 dispersion forces is bigger than the dipole dipole interactions I should say 436 00:11:43,370 --> 00:11:43,380 dipole dipole interactions I should say 437 00:11:43,380 --> 00:11:47,069 dipole dipole interactions I should say particularly if you have large molecules 438 00:11:47,069 --> 00:11:47,079 particularly if you have large molecules 439 00:11:47,079 --> 00:11:50,550 particularly if you have large molecules big molecules than the dispersion forces 440 00:11:50,550 --> 00:11:50,560 big molecules than the dispersion forces 441 00:11:50,560 --> 00:11:52,699 big molecules than the dispersion forces or the energy corresponding to that 442 00:11:52,699 --> 00:11:52,709 or the energy corresponding to that 443 00:11:52,709 --> 00:11:56,879 or the energy corresponding to that dispersion forces attractions is much 444 00:11:56,879 --> 00:11:56,889 dispersion forces attractions is much 445 00:11:56,889 --> 00:12:00,110 dispersion forces attractions is much higher than the dipole dipole forces 446 00:12:00,110 --> 00:12:00,120 higher than the dipole dipole forces 447 00:12:00,120 --> 00:12:03,509 higher than the dipole dipole forces attraction energies now hydrogen bonding 448 00:12:03,509 --> 00:12:03,519 attraction energies now hydrogen bonding 449 00:12:03,519 --> 00:12:07,740 attraction energies now hydrogen bonding again only present in compounds that has 450 00:12:07,740 --> 00:12:07,750 again only present in compounds that has 451 00:12:07,750 --> 00:12:09,870 again only present in compounds that has those hydrogen bonded to the most 452 00:12:09,870 --> 00:12:09,880 those hydrogen bonded to the most 453 00:12:09,880 --> 00:12:12,000 those hydrogen bonded to the most electronegative element and also a lone 454 00:12:12,000 --> 00:12:12,010 electronegative element and also a lone 455 00:12:12,010 --> 00:12:13,620 electronegative element and also a lone pair and those most electronegative 456 00:12:13,620 --> 00:12:13,630 pair and those most electronegative 457 00:12:13,630 --> 00:12:17,429 pair and those most electronegative element if you look at the amount or the 458 00:12:17,429 --> 00:12:17,439 element if you look at the amount or the 459 00:12:17,439 --> 00:12:20,250 element if you look at the amount or the the range of the energy corresponding to 460 00:12:20,250 --> 00:12:20,260 the range of the energy corresponding to 461 00:12:20,260 --> 00:12:22,829 the range of the energy corresponding to hydrogen bonding between 10 and 40 462 00:12:22,829 --> 00:12:22,839 hydrogen bonding between 10 and 40 463 00:12:22,839 --> 00:12:24,840 hydrogen bonding between 10 and 40 kilojoules per mole what does that means 464 00:12:24,840 --> 00:12:24,850 kilojoules per mole what does that means 465 00:12:24,850 --> 00:12:27,329 kilojoules per mole what does that means that simply means that among these three 466 00:12:27,329 --> 00:12:27,339 that simply means that among these three 467 00:12:27,339 --> 00:12:30,179 that simply means that among these three years the most important interactions is 468 00:12:30,179 --> 00:12:30,189 years the most important interactions is 469 00:12:30,189 --> 00:12:32,340 years the most important interactions is the hydrogen bonding intermolecular 470 00:12:32,340 --> 00:12:32,350 the hydrogen bonding intermolecular 471 00:12:32,350 --> 00:12:34,559 the hydrogen bonding intermolecular interactions is the hydrogen bonding 472 00:12:34,559 --> 00:12:34,569 interactions is the hydrogen bonding 473 00:12:34,569 --> 00:12:37,319 interactions is the hydrogen bonding because you see it goes up to 40 474 00:12:37,319 --> 00:12:37,329 because you see it goes up to 40 475 00:12:37,329 --> 00:12:39,230 because you see it goes up to 40 kilojoules per mole for 476 00:12:39,230 --> 00:12:39,240 kilojoules per mole for 477 00:12:39,240 --> 00:12:42,679 kilojoules per mole for now I enjoy both forces as I try to show 478 00:12:42,679 --> 00:12:42,689 now I enjoy both forces as I try to show 479 00:12:42,689 --> 00:12:44,989 now I enjoy both forces as I try to show you over here and that is pretty strong 480 00:12:44,989 --> 00:12:44,999 you over here and that is pretty strong 481 00:12:44,999 --> 00:12:47,090 you over here and that is pretty strong also such as it says sodium chloride 482 00:12:47,090 --> 00:12:47,100 also such as it says sodium chloride 483 00:12:47,100 --> 00:12:49,999 also such as it says sodium chloride dissolved in water right and the 484 00:12:49,999 --> 00:12:50,009 dissolved in water right and the 485 00:12:50,009 --> 00:12:53,269 dissolved in water right and the energies corresponding to that ion 486 00:12:53,269 --> 00:12:53,279 energies corresponding to that ion 487 00:12:53,279 --> 00:12:56,179 energies corresponding to that ion dipole force is about 50 kilo joules or 488 00:12:56,179 --> 00:12:56,189 dipole force is about 50 kilo joules or 489 00:12:56,189 --> 00:12:58,309 dipole force is about 50 kilo joules or higher so that's pretty strong as a 490 00:12:58,309 --> 00:12:58,319 higher so that's pretty strong as a 491 00:12:58,319 --> 00:13:01,460 higher so that's pretty strong as a matter of fact now if you have ionic 492 00:13:01,460 --> 00:13:01,470 matter of fact now if you have ionic 493 00:13:01,470 --> 00:13:04,669 matter of fact now if you have ionic compounds in solid a game like potassium 494 00:13:04,669 --> 00:13:04,679 compounds in solid a game like potassium 495 00:13:04,679 --> 00:13:06,829 compounds in solid a game like potassium bromide ammonium nitrate these are eye 496 00:13:06,829 --> 00:13:06,839 bromide ammonium nitrate these are eye 497 00:13:06,839 --> 00:13:10,009 bromide ammonium nitrate these are eye on ik compound solid and the ionic bond 498 00:13:10,009 --> 00:13:10,019 on ik compound solid and the ionic bond 499 00:13:10,019 --> 00:13:12,919 on ik compound solid and the ionic bond energy here remember is determined by 500 00:13:12,919 --> 00:13:12,929 energy here remember is determined by 501 00:13:12,929 --> 00:13:15,859 energy here remember is determined by the lettuce energy is about 150 502 00:13:15,859 --> 00:13:15,869 the lettuce energy is about 150 503 00:13:15,869 --> 00:13:17,929 the lettuce energy is about 150 kilojoules per mole again you see this 504 00:13:17,929 --> 00:13:17,939 kilojoules per mole again you see this 505 00:13:17,939 --> 00:13:21,109 kilojoules per mole again you see this is considered as a chemical bond ionic 506 00:13:21,109 --> 00:13:21,119 is considered as a chemical bond ionic 507 00:13:21,119 --> 00:13:23,980 is considered as a chemical bond ionic bond much higher than the other 508 00:13:23,980 --> 00:13:23,990 bond much higher than the other 509 00:13:23,990 --> 00:13:28,179 bond much higher than the other intermolecular forces that causes the 510 00:13:28,179 --> 00:13:28,189 intermolecular forces that causes the 511 00:13:28,189 --> 00:13:33,019 intermolecular forces that causes the interaction energies again now our 512 00:13:33,019 --> 00:13:33,029 interaction energies again now our 513 00:13:33,029 --> 00:13:35,119 interaction energies again now our liquid property is affected by 514 00:13:35,119 --> 00:13:35,129 liquid property is affected by 515 00:13:35,129 --> 00:13:36,769 liquid property is affected by intermolecular forces remember we said 516 00:13:36,769 --> 00:13:36,779 intermolecular forces remember we said 517 00:13:36,779 --> 00:13:38,900 intermolecular forces remember we said that these forces intermolecular forces 518 00:13:38,900 --> 00:13:38,910 that these forces intermolecular forces 519 00:13:38,910 --> 00:13:41,359 that these forces intermolecular forces are much weaker than the chemical bond 520 00:13:41,359 --> 00:13:41,369 are much weaker than the chemical bond 521 00:13:41,369 --> 00:13:45,079 are much weaker than the chemical bond that is intramolecular forces but they 522 00:13:45,079 --> 00:13:45,089 that is intramolecular forces but they 523 00:13:45,089 --> 00:13:49,730 that is intramolecular forces but they do have very great effect on their 524 00:13:49,730 --> 00:13:49,740 do have very great effect on their 525 00:13:49,740 --> 00:13:52,369 do have very great effect on their physical properties and what are these 526 00:13:52,369 --> 00:13:52,379 physical properties and what are these 527 00:13:52,379 --> 00:13:54,939 physical properties and what are these physical properties boiling point 528 00:13:54,939 --> 00:13:54,949 physical properties boiling point 529 00:13:54,949 --> 00:13:57,559 physical properties boiling point actually we talked about that a little 530 00:13:57,559 --> 00:13:57,569 actually we talked about that a little 531 00:13:57,569 --> 00:14:00,850 actually we talked about that a little bit and the mountain point of solids and 532 00:14:00,850 --> 00:14:00,860 bit and the mountain point of solids and 533 00:14:00,860 --> 00:14:04,189 bit and the mountain point of solids and vapour pressure we will talk about here 534 00:14:04,189 --> 00:14:04,199 vapour pressure we will talk about here 535 00:14:04,199 --> 00:14:05,359 vapour pressure we will talk about here and the boiling point 536 00:14:05,359 --> 00:14:05,369 and the boiling point 537 00:14:05,369 --> 00:14:08,749 and the boiling point viscosity surface tension and capillary 538 00:14:08,749 --> 00:14:08,759 viscosity surface tension and capillary 539 00:14:08,759 --> 00:14:12,199 viscosity surface tension and capillary action particularly these three boiling 540 00:14:12,199 --> 00:14:12,209 action particularly these three boiling 541 00:14:12,209 --> 00:14:14,090 action particularly these three boiling point viscosity surface tension 542 00:14:14,090 --> 00:14:14,100 point viscosity surface tension 543 00:14:14,100 --> 00:14:15,639 point viscosity surface tension capillary 544 00:14:15,639 --> 00:14:15,649 capillary 545 00:14:15,649 --> 00:14:19,009 capillary relates to the liquids more to the 546 00:14:19,009 --> 00:14:19,019 relates to the liquids more to the 547 00:14:19,019 --> 00:14:21,139 relates to the liquids more to the liquids as a matter of fact now let's 548 00:14:21,139 --> 00:14:21,149 liquids as a matter of fact now let's 549 00:14:21,149 --> 00:14:25,160 liquids as a matter of fact now let's look at these now viscosity is simply 550 00:14:25,160 --> 00:14:25,170 look at these now viscosity is simply 551 00:14:25,170 --> 00:14:29,960 look at these now viscosity is simply define resistance of a liquid to flow is 552 00:14:29,960 --> 00:14:29,970 define resistance of a liquid to flow is 553 00:14:29,970 --> 00:14:33,220 define resistance of a liquid to flow is called viscosity right now here we have 554 00:14:33,220 --> 00:14:33,230 called viscosity right now here we have 555 00:14:33,230 --> 00:14:37,850 called viscosity right now here we have simply same diameter holes here these 556 00:14:37,850 --> 00:14:37,860 simply same diameter holes here these 557 00:14:37,860 --> 00:14:41,150 simply same diameter holes here these are the same diameter pipes like this 558 00:14:41,150 --> 00:14:41,160 are the same diameter pipes like this 559 00:14:41,160 --> 00:14:45,530 are the same diameter pipes like this and we have oil simply falling down here 560 00:14:45,530 --> 00:14:45,540 and we have oil simply falling down here 561 00:14:45,540 --> 00:14:50,269 and we have oil simply falling down here pouring down here and you see again this 562 00:14:50,269 --> 00:14:50,279 pouring down here and you see again this 563 00:14:50,279 --> 00:14:52,370 pouring down here and you see again this oil has much higher 564 00:14:52,370 --> 00:14:52,380 oil has much higher 565 00:14:52,380 --> 00:14:54,470 oil has much higher viscosity than this one because if you 566 00:14:54,470 --> 00:14:54,480 viscosity than this one because if you 567 00:14:54,480 --> 00:14:56,930 viscosity than this one because if you start filling them at the same time you 568 00:14:56,930 --> 00:14:56,940 start filling them at the same time you 569 00:14:56,940 --> 00:15:01,430 start filling them at the same time you see much less liquid oil passes through 570 00:15:01,430 --> 00:15:01,440 see much less liquid oil passes through 571 00:15:01,440 --> 00:15:04,370 see much less liquid oil passes through the same hole same sized hole here than 572 00:15:04,370 --> 00:15:04,380 the same hole same sized hole here than 573 00:15:04,380 --> 00:15:07,450 the same hole same sized hole here than here that means that this oil is 574 00:15:07,450 --> 00:15:07,460 here that means that this oil is 575 00:15:07,460 --> 00:15:11,120 here that means that this oil is resistance to flow and we call it more 576 00:15:11,120 --> 00:15:11,130 resistance to flow and we call it more 577 00:15:11,130 --> 00:15:13,550 resistance to flow and we call it more viscous than this so if he compared the 578 00:15:13,550 --> 00:15:13,560 viscous than this so if he compared the 579 00:15:13,560 --> 00:15:16,070 viscous than this so if he compared the viscosity of these two oils this is 580 00:15:16,070 --> 00:15:16,080 viscosity of these two oils this is 581 00:15:16,080 --> 00:15:19,160 viscosity of these two oils this is actually more viscous or higher 582 00:15:19,160 --> 00:15:19,170 actually more viscous or higher 583 00:15:19,170 --> 00:15:21,530 actually more viscous or higher viscosity this is lower viscosity again 584 00:15:21,530 --> 00:15:21,540 viscosity this is lower viscosity again 585 00:15:21,540 --> 00:15:25,670 viscosity this is lower viscosity again now Miss Cassity increases with strong 586 00:15:25,670 --> 00:15:25,680 now Miss Cassity increases with strong 587 00:15:25,680 --> 00:15:27,560 now Miss Cassity increases with strong intermolecular forces and decreases with 588 00:15:27,560 --> 00:15:27,570 intermolecular forces and decreases with 589 00:15:27,570 --> 00:15:29,150 intermolecular forces and decreases with higher temperature now this is really 590 00:15:29,150 --> 00:15:29,160 higher temperature now this is really 591 00:15:29,160 --> 00:15:29,960 higher temperature now this is really important 592 00:15:29,960 --> 00:15:29,970 important 593 00:15:29,970 --> 00:15:34,330 important the stronger the intermolecular forces 594 00:15:34,330 --> 00:15:34,340 the stronger the intermolecular forces 595 00:15:34,340 --> 00:15:38,300 the stronger the intermolecular forces between the molecules of the liquid the 596 00:15:38,300 --> 00:15:38,310 between the molecules of the liquid the 597 00:15:38,310 --> 00:15:41,680 between the molecules of the liquid the higher will be the viscosity right and 598 00:15:41,680 --> 00:15:41,690 higher will be the viscosity right and 599 00:15:41,690 --> 00:15:45,320 higher will be the viscosity right and the weaker the attraction between the 600 00:15:45,320 --> 00:15:45,330 the weaker the attraction between the 601 00:15:45,330 --> 00:15:47,240 the weaker the attraction between the molecules the lower will be the 602 00:15:47,240 --> 00:15:47,250 molecules the lower will be the 603 00:15:47,250 --> 00:15:51,070 molecules the lower will be the viscosity again now these two actually 604 00:15:51,070 --> 00:15:51,080 viscosity again now these two actually 605 00:15:51,080 --> 00:15:55,250 viscosity again now these two actually sae 40 and sae 10 do you know what they 606 00:15:55,250 --> 00:15:55,260 sae 40 and sae 10 do you know what they 607 00:15:55,260 --> 00:16:02,510 sae 40 and sae 10 do you know what they are they're actually if you ever used if 608 00:16:02,510 --> 00:16:02,520 are they're actually if you ever used if 609 00:16:02,520 --> 00:16:06,110 are they're actually if you ever used if you ever put engine oil in your engine 610 00:16:06,110 --> 00:16:06,120 you ever put engine oil in your engine 611 00:16:06,120 --> 00:16:10,490 you ever put engine oil in your engine car engine right so you use the oil 612 00:16:10,490 --> 00:16:10,500 car engine right so you use the oil 613 00:16:10,500 --> 00:16:14,120 car engine right so you use the oil which have sae 40 this indicates the 614 00:16:14,120 --> 00:16:14,130 which have sae 40 this indicates the 615 00:16:14,130 --> 00:16:18,620 which have sae 40 this indicates the viscosity of this oil or sae 10 now 616 00:16:18,620 --> 00:16:18,630 viscosity of this oil or sae 10 now 617 00:16:18,630 --> 00:16:20,450 viscosity of this oil or sae 10 now which one is more viscous this one is 618 00:16:20,450 --> 00:16:20,460 which one is more viscous this one is 619 00:16:20,460 --> 00:16:23,060 which one is more viscous this one is more viscous right higher viscosity this 620 00:16:23,060 --> 00:16:23,070 more viscous right higher viscosity this 621 00:16:23,070 --> 00:16:24,800 more viscous right higher viscosity this one is lower viscosity 622 00:16:24,800 --> 00:16:24,810 one is lower viscosity 623 00:16:24,810 --> 00:16:30,050 one is lower viscosity now since the this Cassetti decreases 624 00:16:30,050 --> 00:16:30,060 now since the this Cassetti decreases 625 00:16:30,060 --> 00:16:33,980 now since the this Cassetti decreases with increase in temperature let me ask 626 00:16:33,980 --> 00:16:33,990 with increase in temperature let me ask 627 00:16:33,990 --> 00:16:40,250 with increase in temperature let me ask you this one of this oil is used in the 628 00:16:40,250 --> 00:16:40,260 you this one of this oil is used in the 629 00:16:40,260 --> 00:16:43,610 you this one of this oil is used in the wintertime the other one is used in the 630 00:16:43,610 --> 00:16:43,620 wintertime the other one is used in the 631 00:16:43,620 --> 00:16:48,860 wintertime the other one is used in the summertime which one for the winter and 632 00:16:48,860 --> 00:16:48,870 summertime which one for the winter and 633 00:16:48,870 --> 00:16:54,300 summertime which one for the winter and which one is for the summer 634 00:16:54,300 --> 00:16:54,310 635 00:16:54,310 --> 00:17:01,030 first one is for what summer right 636 00:17:01,030 --> 00:17:01,040 first one is for what summer right 637 00:17:01,040 --> 00:17:04,659 first one is for what summer right because then the temperature is high in 638 00:17:04,659 --> 00:17:04,669 because then the temperature is high in 639 00:17:04,669 --> 00:17:06,549 because then the temperature is high in the summer so the viscosity will drop 640 00:17:06,549 --> 00:17:06,559 the summer so the viscosity will drop 641 00:17:06,559 --> 00:17:10,319 the summer so the viscosity will drop and this one is for the winter right 642 00:17:10,319 --> 00:17:10,329 and this one is for the winter right 643 00:17:10,329 --> 00:17:14,130 and this one is for the winter right usually again right now they have the 644 00:17:14,130 --> 00:17:14,140 usually again right now they have the 645 00:17:14,140 --> 00:17:17,650 usually again right now they have the engine oils which comprises both of 646 00:17:17,650 --> 00:17:17,660 engine oils which comprises both of 647 00:17:17,660 --> 00:17:19,659 engine oils which comprises both of these properties one kind so you put 648 00:17:19,659 --> 00:17:19,669 these properties one kind so you put 649 00:17:19,669 --> 00:17:22,860 these properties one kind so you put that in the summer and in winter too but 650 00:17:22,860 --> 00:17:22,870 that in the summer and in winter too but 651 00:17:22,870 --> 00:17:26,829 that in the summer and in winter too but in all times you have to change the 652 00:17:26,829 --> 00:17:26,839 in all times you have to change the 653 00:17:26,839 --> 00:17:29,350 in all times you have to change the engine oil into winter time and also in 654 00:17:29,350 --> 00:17:29,360 engine oil into winter time and also in 655 00:17:29,360 --> 00:17:31,690 engine oil into winter time and also in a summer time so because you have to use 656 00:17:31,690 --> 00:17:31,700 a summer time so because you have to use 657 00:17:31,700 --> 00:17:35,440 a summer time so because you have to use different viscosity oils again in the 658 00:17:35,440 --> 00:17:35,450 different viscosity oils again in the 659 00:17:35,450 --> 00:17:37,270 different viscosity oils again in the summer time you use high viscosity oil 660 00:17:37,270 --> 00:17:37,280 summer time you use high viscosity oil 661 00:17:37,280 --> 00:17:39,340 summer time you use high viscosity oil in a very time you use low viscosity oil 662 00:17:39,340 --> 00:17:39,350 in a very time you use low viscosity oil 663 00:17:39,350 --> 00:17:42,220 in a very time you use low viscosity oil to make the engine properly work 664 00:17:42,220 --> 00:17:42,230 to make the engine properly work 665 00:17:42,230 --> 00:17:45,880 to make the engine properly work function again right okay again you see 666 00:17:45,880 --> 00:17:45,890 function again right okay again you see 667 00:17:45,890 --> 00:17:48,370 function again right okay again you see here the viscosity of series of 668 00:17:48,370 --> 00:17:48,380 here the viscosity of series of 669 00:17:48,380 --> 00:17:51,340 here the viscosity of series of hydrocarbons the viscosity increases as 670 00:17:51,340 --> 00:17:51,350 hydrocarbons the viscosity increases as 671 00:17:51,350 --> 00:17:54,510 hydrocarbons the viscosity increases as we go down why because the 672 00:17:54,510 --> 00:17:54,520 we go down why because the 673 00:17:54,520 --> 00:17:58,720 we go down why because the intermolecular forces increases what 674 00:17:58,720 --> 00:17:58,730 intermolecular forces increases what 675 00:17:58,730 --> 00:18:01,120 intermolecular forces increases what intermolecular forces are present among 676 00:18:01,120 --> 00:18:01,130 intermolecular forces are present among 677 00:18:01,130 --> 00:18:07,419 intermolecular forces are present among these hydrocarbons dispersion forces 678 00:18:07,419 --> 00:18:07,429 these hydrocarbons dispersion forces 679 00:18:07,429 --> 00:18:09,789 these hydrocarbons dispersion forces right only dispersion forces because 680 00:18:09,789 --> 00:18:09,799 right only dispersion forces because 681 00:18:09,799 --> 00:18:11,649 right only dispersion forces because these are not polar molecules they're 682 00:18:11,649 --> 00:18:11,659 these are not polar molecules they're 683 00:18:11,659 --> 00:18:15,159 these are not polar molecules they're nonpolar molecules only intermolecular 684 00:18:15,159 --> 00:18:15,169 nonpolar molecules only intermolecular 685 00:18:15,169 --> 00:18:17,950 nonpolar molecules only intermolecular forces the dispersion and remember the 686 00:18:17,950 --> 00:18:17,960 forces the dispersion and remember the 687 00:18:17,960 --> 00:18:20,919 forces the dispersion and remember the larger the molecule the higher the 688 00:18:20,919 --> 00:18:20,929 larger the molecule the higher the 689 00:18:20,929 --> 00:18:24,190 larger the molecule the higher the dispersion force means that they came 690 00:18:24,190 --> 00:18:24,200 dispersion force means that they came 691 00:18:24,200 --> 00:18:27,630 dispersion force means that they came for example here have highest 692 00:18:27,630 --> 00:18:27,640 for example here have highest 693 00:18:27,640 --> 00:18:30,370 for example here have highest intermolecular forces and its viscosity 694 00:18:30,370 --> 00:18:30,380 intermolecular forces and its viscosity 695 00:18:30,380 --> 00:18:34,330 intermolecular forces and its viscosity is highest higher the viscosity actually 696 00:18:34,330 --> 00:18:34,340 is highest higher the viscosity actually 697 00:18:34,340 --> 00:18:36,010 is highest higher the viscosity actually higher the intermolecular forces or 698 00:18:36,010 --> 00:18:36,020 higher the intermolecular forces or 699 00:18:36,020 --> 00:18:40,149 higher the intermolecular forces or vice-versa now surface tension and is 700 00:18:40,149 --> 00:18:40,159 vice-versa now surface tension and is 701 00:18:40,159 --> 00:18:45,789 vice-versa now surface tension and is another property of liquids which is 702 00:18:45,789 --> 00:18:45,799 another property of liquids which is 703 00:18:45,799 --> 00:18:48,520 another property of liquids which is determined actually by the 704 00:18:48,520 --> 00:18:48,530 determined actually by the 705 00:18:48,530 --> 00:18:51,430 determined actually by the intermolecular forces here again we have 706 00:18:51,430 --> 00:18:51,440 intermolecular forces here again we have 707 00:18:51,440 --> 00:18:55,649 intermolecular forces here again we have water and you have a bug which simply 708 00:18:55,649 --> 00:18:55,659 water and you have a bug which simply 709 00:18:55,659 --> 00:18:58,299 water and you have a bug which simply stays on the water it can walk on the 710 00:18:58,299 --> 00:18:58,309 stays on the water it can walk on the 711 00:18:58,309 --> 00:19:01,510 stays on the water it can walk on the water without immersion into liquid 712 00:19:01,510 --> 00:19:01,520 water without immersion into liquid 713 00:19:01,520 --> 00:19:03,610 water without immersion into liquid water as a matter of fact because water 714 00:19:03,610 --> 00:19:03,620 water as a matter of fact because water 715 00:19:03,620 --> 00:19:06,980 water as a matter of fact because water says act as if has a skin on 716 00:19:06,980 --> 00:19:06,990 says act as if has a skin on 717 00:19:06,990 --> 00:19:09,980 says act as if has a skin on due to extra inward forces on its 718 00:19:09,980 --> 00:19:09,990 due to extra inward forces on its 719 00:19:09,990 --> 00:19:12,169 due to extra inward forces on its surface it says those forces are called 720 00:19:12,169 --> 00:19:12,179 surface it says those forces are called 721 00:19:12,179 --> 00:19:14,720 surface it says those forces are called surface tension let's try to examine 722 00:19:14,720 --> 00:19:14,730 surface tension let's try to examine 723 00:19:14,730 --> 00:19:17,780 surface tension let's try to examine what is surface tension means what is 724 00:19:17,780 --> 00:19:17,790 what is surface tension means what is 725 00:19:17,790 --> 00:19:20,240 what is surface tension means what is the origin why we have surface tension 726 00:19:20,240 --> 00:19:20,250 the origin why we have surface tension 727 00:19:20,250 --> 00:19:23,570 the origin why we have surface tension right off the liquids and how it changes 728 00:19:23,570 --> 00:19:23,580 right off the liquids and how it changes 729 00:19:23,580 --> 00:19:26,900 right off the liquids and how it changes now let's consider this suppose that 730 00:19:26,900 --> 00:19:26,910 now let's consider this suppose that 731 00:19:26,910 --> 00:19:29,960 now let's consider this suppose that this is a liquid and these are the 732 00:19:29,960 --> 00:19:29,970 this is a liquid and these are the 733 00:19:29,970 --> 00:19:32,419 this is a liquid and these are the molecule may be just water okay this is 734 00:19:32,419 --> 00:19:32,429 molecule may be just water okay this is 735 00:19:32,429 --> 00:19:35,450 molecule may be just water okay this is just water in a beaker like this and 736 00:19:35,450 --> 00:19:35,460 just water in a beaker like this and 737 00:19:35,460 --> 00:19:37,460 just water in a beaker like this and there's our this is the surface of the 738 00:19:37,460 --> 00:19:37,470 there's our this is the surface of the 739 00:19:37,470 --> 00:19:39,620 there's our this is the surface of the liquid and this is the bulk inside the 740 00:19:39,620 --> 00:19:39,630 liquid and this is the bulk inside the 741 00:19:39,630 --> 00:19:43,220 liquid and this is the bulk inside the ball now since there is intermolecular 742 00:19:43,220 --> 00:19:43,230 ball now since there is intermolecular 743 00:19:43,230 --> 00:19:46,460 ball now since there is intermolecular forces present between the molecules of 744 00:19:46,460 --> 00:19:46,470 forces present between the molecules of 745 00:19:46,470 --> 00:19:49,430 forces present between the molecules of the liquid and now let's consider two 746 00:19:49,430 --> 00:19:49,440 the liquid and now let's consider two 747 00:19:49,440 --> 00:19:53,299 the liquid and now let's consider two molecules one is on the surface this 748 00:19:53,299 --> 00:19:53,309 molecules one is on the surface this 749 00:19:53,309 --> 00:19:55,730 molecules one is on the surface this molecule here the other one is in the 750 00:19:55,730 --> 00:19:55,740 molecule here the other one is in the 751 00:19:55,740 --> 00:19:59,870 molecule here the other one is in the ball this molecule here and think about 752 00:19:59,870 --> 00:19:59,880 ball this molecule here and think about 753 00:19:59,880 --> 00:20:02,450 ball this molecule here and think about the forces intermolecular forces that 754 00:20:02,450 --> 00:20:02,460 the forces intermolecular forces that 755 00:20:02,460 --> 00:20:06,680 the forces intermolecular forces that acting on those now if you consider this 756 00:20:06,680 --> 00:20:06,690 acting on those now if you consider this 757 00:20:06,690 --> 00:20:09,620 acting on those now if you consider this one here so this molecule is attracted 758 00:20:09,620 --> 00:20:09,630 one here so this molecule is attracted 759 00:20:09,630 --> 00:20:12,799 one here so this molecule is attracted by a force with this molecule and this 760 00:20:12,799 --> 00:20:12,809 by a force with this molecule and this 761 00:20:12,809 --> 00:20:14,990 by a force with this molecule and this molecule this molecule that molecule and 762 00:20:14,990 --> 00:20:15,000 molecule this molecule that molecule and 763 00:20:15,000 --> 00:20:17,600 molecule this molecule that molecule and so on now if you sum up all of these 764 00:20:17,600 --> 00:20:17,610 so on now if you sum up all of these 765 00:20:17,610 --> 00:20:21,190 so on now if you sum up all of these attraction forces the net result will be 766 00:20:21,190 --> 00:20:21,200 attraction forces the net result will be 767 00:20:21,200 --> 00:20:25,040 attraction forces the net result will be zero right now that means that there is 768 00:20:25,040 --> 00:20:25,050 zero right now that means that there is 769 00:20:25,050 --> 00:20:29,270 zero right now that means that there is no net force acting in any direction for 770 00:20:29,270 --> 00:20:29,280 no net force acting in any direction for 771 00:20:29,280 --> 00:20:32,240 no net force acting in any direction for this molecule which is in the ball in a 772 00:20:32,240 --> 00:20:32,250 this molecule which is in the ball in a 773 00:20:32,250 --> 00:20:34,730 this molecule which is in the ball in a liquid now consider the molecule at the 774 00:20:34,730 --> 00:20:34,740 liquid now consider the molecule at the 775 00:20:34,740 --> 00:20:37,460 liquid now consider the molecule at the surface this molecule so this molecule 776 00:20:37,460 --> 00:20:37,470 surface this molecule so this molecule 777 00:20:37,470 --> 00:20:39,500 surface this molecule so this molecule will be attracted by this molecule here 778 00:20:39,500 --> 00:20:39,510 will be attracted by this molecule here 779 00:20:39,510 --> 00:20:41,630 will be attracted by this molecule here in this direction and that directions 780 00:20:41,630 --> 00:20:41,640 in this direction and that directions 781 00:20:41,640 --> 00:20:43,730 in this direction and that directions this direction and that direction if you 782 00:20:43,730 --> 00:20:43,740 this direction and that direction if you 783 00:20:43,740 --> 00:20:46,430 this direction and that direction if you take the combinations of all of these 784 00:20:46,430 --> 00:20:46,440 take the combinations of all of these 785 00:20:46,440 --> 00:20:50,090 take the combinations of all of these forces it will not be equal to 0 it will 786 00:20:50,090 --> 00:20:50,100 forces it will not be equal to 0 it will 787 00:20:50,100 --> 00:20:52,549 forces it will not be equal to 0 it will be equal to a net force which will be 788 00:20:52,549 --> 00:20:52,559 be equal to a net force which will be 789 00:20:52,559 --> 00:20:55,669 be equal to a net force which will be downward here what does that means that 790 00:20:55,669 --> 00:20:55,679 downward here what does that means that 791 00:20:55,679 --> 00:20:58,400 downward here what does that means that means that all the molecules at the 792 00:20:58,400 --> 00:20:58,410 means that all the molecules at the 793 00:20:58,410 --> 00:21:02,120 means that all the molecules at the surface of the liquid will be pulled in 794 00:21:02,120 --> 00:21:02,130 surface of the liquid will be pulled in 795 00:21:02,130 --> 00:21:06,049 surface of the liquid will be pulled in by a force into the liquid right so now 796 00:21:06,049 --> 00:21:06,059 by a force into the liquid right so now 797 00:21:06,059 --> 00:21:10,910 by a force into the liquid right so now this simply creates a tension at the 798 00:21:10,910 --> 00:21:10,920 this simply creates a tension at the 799 00:21:10,920 --> 00:21:14,630 this simply creates a tension at the surface and and that simply makes the 800 00:21:14,630 --> 00:21:14,640 surface and and that simply makes the 801 00:21:14,640 --> 00:21:17,120 surface and and that simply makes the surface tension possible again 802 00:21:17,120 --> 00:21:17,130 surface tension possible again 803 00:21:17,130 --> 00:21:20,250 surface tension possible again so now that 804 00:21:20,250 --> 00:21:20,260 so now that 805 00:21:20,260 --> 00:21:24,150 so now that is why actually liquid molecules 806 00:21:24,150 --> 00:21:24,160 is why actually liquid molecules 807 00:21:24,160 --> 00:21:26,450 is why actually liquid molecules particularly have strong intermolecular 808 00:21:26,450 --> 00:21:26,460 particularly have strong intermolecular 809 00:21:26,460 --> 00:21:30,840 particularly have strong intermolecular attractions try to take the shape of a 810 00:21:30,840 --> 00:21:30,850 attractions try to take the shape of a 811 00:21:30,850 --> 00:21:34,890 attractions try to take the shape of a sphere if you take it water drop and the 812 00:21:34,890 --> 00:21:34,900 sphere if you take it water drop and the 813 00:21:34,900 --> 00:21:36,510 sphere if you take it water drop and the shape of the water drop sort of 814 00:21:36,510 --> 00:21:36,520 shape of the water drop sort of 815 00:21:36,520 --> 00:21:40,130 shape of the water drop sort of spherical right spherical or if you take 816 00:21:40,130 --> 00:21:40,140 spherical right spherical or if you take 817 00:21:40,140 --> 00:21:43,710 spherical right spherical or if you take liquid mercury and just drop it it is 818 00:21:43,710 --> 00:21:43,720 liquid mercury and just drop it it is 819 00:21:43,720 --> 00:21:46,650 liquid mercury and just drop it it is almost spherical right almost vertical 820 00:21:46,650 --> 00:21:46,660 almost spherical right almost vertical 821 00:21:46,660 --> 00:21:53,450 almost spherical right almost vertical why because the intermolecular forces 822 00:21:53,450 --> 00:21:53,460 why because the intermolecular forces 823 00:21:53,460 --> 00:21:58,590 why because the intermolecular forces try to minimize the surface area of the 824 00:21:58,590 --> 00:21:58,600 try to minimize the surface area of the 825 00:21:58,600 --> 00:22:01,290 try to minimize the surface area of the liquids right because all the molecules 826 00:22:01,290 --> 00:22:01,300 liquids right because all the molecules 827 00:22:01,300 --> 00:22:04,220 liquids right because all the molecules at the surface are pulled in so the 828 00:22:04,220 --> 00:22:04,230 at the surface are pulled in so the 829 00:22:04,230 --> 00:22:07,020 at the surface are pulled in so the liquid in fact which have strong 830 00:22:07,020 --> 00:22:07,030 liquid in fact which have strong 831 00:22:07,030 --> 00:22:09,660 liquid in fact which have strong attractions try to minimize its surface 832 00:22:09,660 --> 00:22:09,670 attractions try to minimize its surface 833 00:22:09,670 --> 00:22:13,800 attractions try to minimize its surface area and the minimum surface area for a 834 00:22:13,800 --> 00:22:13,810 area and the minimum surface area for a 835 00:22:13,810 --> 00:22:16,530 area and the minimum surface area for a given amount of substance will only be 836 00:22:16,530 --> 00:22:16,540 given amount of substance will only be 837 00:22:16,540 --> 00:22:18,720 given amount of substance will only be obtained if the shape of that substance 838 00:22:18,720 --> 00:22:18,730 obtained if the shape of that substance 839 00:22:18,730 --> 00:22:23,630 obtained if the shape of that substance is sphere right so that's why actually 840 00:22:23,630 --> 00:22:23,640 is sphere right so that's why actually 841 00:22:23,640 --> 00:22:27,090 is sphere right so that's why actually strong intermolecular attractions if 842 00:22:27,090 --> 00:22:27,100 strong intermolecular attractions if 843 00:22:27,100 --> 00:22:30,060 strong intermolecular attractions if present in a liquid and it's drop will 844 00:22:30,060 --> 00:22:30,070 present in a liquid and it's drop will 845 00:22:30,070 --> 00:22:33,210 present in a liquid and it's drop will be more like a sphere now in the mercury 846 00:22:33,210 --> 00:22:33,220 be more like a sphere now in the mercury 847 00:22:33,220 --> 00:22:34,980 be more like a sphere now in the mercury cases mercury has very very strong 848 00:22:34,980 --> 00:22:34,990 cases mercury has very very strong 849 00:22:34,990 --> 00:22:37,830 cases mercury has very very strong internal inter atomic attractions there 850 00:22:37,830 --> 00:22:37,840 internal inter atomic attractions there 851 00:22:37,840 --> 00:22:39,600 internal inter atomic attractions there in the liquid mercury 852 00:22:39,600 --> 00:22:39,610 in the liquid mercury 853 00:22:39,610 --> 00:22:42,540 in the liquid mercury and if you take a liquid mercury drop 854 00:22:42,540 --> 00:22:42,550 and if you take a liquid mercury drop 855 00:22:42,550 --> 00:22:44,190 and if you take a liquid mercury drop and put it on the table it will be 856 00:22:44,190 --> 00:22:44,200 and put it on the table it will be 857 00:22:44,200 --> 00:22:47,040 and put it on the table it will be almost spherical almost spherical but 858 00:22:47,040 --> 00:22:47,050 almost spherical almost spherical but 859 00:22:47,050 --> 00:22:49,590 almost spherical almost spherical but the water is also like that so actually 860 00:22:49,590 --> 00:22:49,600 the water is also like that so actually 861 00:22:49,600 --> 00:22:53,670 the water is also like that so actually the surface tension related or the 862 00:22:53,670 --> 00:22:53,680 the surface tension related or the 863 00:22:53,680 --> 00:22:55,920 the surface tension related or the measure or I should say off the surface 864 00:22:55,920 --> 00:22:55,930 measure or I should say off the surface 865 00:22:55,930 --> 00:22:58,680 measure or I should say off the surface session is the amount of energy required 866 00:22:58,680 --> 00:22:58,690 session is the amount of energy required 867 00:22:58,690 --> 00:23:02,100 session is the amount of energy required to create unit amount of surface from a 868 00:23:02,100 --> 00:23:02,110 to create unit amount of surface from a 869 00:23:02,110 --> 00:23:05,040 to create unit amount of surface from a liquids right and that creating a 870 00:23:05,040 --> 00:23:05,050 liquids right and that creating a 871 00:23:05,050 --> 00:23:08,370 liquids right and that creating a surface will require energy because all 872 00:23:08,370 --> 00:23:08,380 surface will require energy because all 873 00:23:08,380 --> 00:23:10,830 surface will require energy because all of the molecules at the surface will be 874 00:23:10,830 --> 00:23:10,840 of the molecules at the surface will be 875 00:23:10,840 --> 00:23:14,490 of the molecules at the surface will be pulled into the liquid so the liquid 876 00:23:14,490 --> 00:23:14,500 pulled into the liquid so the liquid 877 00:23:14,500 --> 00:23:16,590 pulled into the liquid so the liquid actually will try to minimize its 878 00:23:16,590 --> 00:23:16,600 actually will try to minimize its 879 00:23:16,600 --> 00:23:19,920 actually will try to minimize its surface and the energy required to make 880 00:23:19,920 --> 00:23:19,930 surface and the energy required to make 881 00:23:19,930 --> 00:23:22,290 surface and the energy required to make that surface area is the viscosity 882 00:23:22,290 --> 00:23:22,300 that surface area is the viscosity 883 00:23:22,300 --> 00:23:25,260 that surface area is the viscosity actually the unit of the viscosity is 884 00:23:25,260 --> 00:23:25,270 actually the unit of the viscosity is 885 00:23:25,270 --> 00:23:28,940 actually the unit of the viscosity is also a meter per Joule per meter per 886 00:23:28,940 --> 00:23:28,950 also a meter per Joule per meter per 887 00:23:28,950 --> 00:23:32,549 also a meter per Joule per meter per against second 888 00:23:32,549 --> 00:23:32,559 889 00:23:32,559 --> 00:23:38,789 okay clear now again how does this 890 00:23:38,789 --> 00:23:38,799 okay clear now again how does this 891 00:23:38,799 --> 00:23:41,490 okay clear now again how does this surface tension changes as you can 892 00:23:41,490 --> 00:23:41,500 surface tension changes as you can 893 00:23:41,500 --> 00:23:44,149 surface tension changes as you can imagine the stronger the intermolecular 894 00:23:44,149 --> 00:23:44,159 imagine the stronger the intermolecular 895 00:23:44,159 --> 00:23:47,820 imagine the stronger the intermolecular forces between the liquids the higher 896 00:23:47,820 --> 00:23:47,830 forces between the liquids the higher 897 00:23:47,830 --> 00:23:51,000 forces between the liquids the higher will be the surface tension of that 898 00:23:51,000 --> 00:23:51,010 will be the surface tension of that 899 00:23:51,010 --> 00:23:53,070 will be the surface tension of that liquid right the high will be the 900 00:23:53,070 --> 00:23:53,080 liquid right the high will be the 901 00:23:53,080 --> 00:23:56,700 liquid right the high will be the surface tension of the liquid now here 902 00:23:56,700 --> 00:23:56,710 surface tension of the liquid now here 903 00:23:56,710 --> 00:24:00,750 surface tension of the liquid now here we have two kinds of interactions or 904 00:24:00,750 --> 00:24:00,760 we have two kinds of interactions or 905 00:24:00,760 --> 00:24:04,380 we have two kinds of interactions or attractions cohesion and adhesion these 906 00:24:04,380 --> 00:24:04,390 attractions cohesion and adhesion these 907 00:24:04,390 --> 00:24:08,370 attractions cohesion and adhesion these two terms now intermolecular forces that 908 00:24:08,370 --> 00:24:08,380 two terms now intermolecular forces that 909 00:24:08,380 --> 00:24:10,710 two terms now intermolecular forces that bind similar molecules to one another 910 00:24:10,710 --> 00:24:10,720 bind similar molecules to one another 911 00:24:10,720 --> 00:24:14,070 bind similar molecules to one another are called cohesive forces what does 912 00:24:14,070 --> 00:24:14,080 are called cohesive forces what does 913 00:24:14,080 --> 00:24:16,789 are called cohesive forces what does that mean that means if you consider 914 00:24:16,789 --> 00:24:16,799 that mean that means if you consider 915 00:24:16,799 --> 00:24:19,919 that mean that means if you consider liquid water in a beaker a glass of 916 00:24:19,919 --> 00:24:19,929 liquid water in a beaker a glass of 917 00:24:19,929 --> 00:24:24,539 liquid water in a beaker a glass of beaker right now they're the attraction 918 00:24:24,539 --> 00:24:24,549 beaker right now they're the attraction 919 00:24:24,549 --> 00:24:29,370 beaker right now they're the attraction between two water molecules is cohesive 920 00:24:29,370 --> 00:24:29,380 between two water molecules is cohesive 921 00:24:29,380 --> 00:24:33,270 between two water molecules is cohesive forces actually right now the 922 00:24:33,270 --> 00:24:33,280 forces actually right now the 923 00:24:33,280 --> 00:24:35,549 forces actually right now the intermolecular forces that bind a 924 00:24:35,549 --> 00:24:35,559 intermolecular forces that bind a 925 00:24:35,559 --> 00:24:38,399 intermolecular forces that bind a substance to a surface surface are 926 00:24:38,399 --> 00:24:38,409 substance to a surface surface are 927 00:24:38,409 --> 00:24:42,299 substance to a surface surface are called adhesive forces so again the 928 00:24:42,299 --> 00:24:42,309 called adhesive forces so again the 929 00:24:42,309 --> 00:24:44,640 called adhesive forces so again the attraction force between the water 930 00:24:44,640 --> 00:24:44,650 attraction force between the water 931 00:24:44,650 --> 00:24:48,980 attraction force between the water molecule and the glass if the water in a 932 00:24:48,980 --> 00:24:48,990 molecule and the glass if the water in a 933 00:24:48,990 --> 00:24:52,080 molecule and the glass if the water in a beaker glass beaker for example that 934 00:24:52,080 --> 00:24:52,090 beaker glass beaker for example that 935 00:24:52,090 --> 00:24:54,779 beaker glass beaker for example that kind of force is called adhesive forces 936 00:24:54,779 --> 00:24:54,789 kind of force is called adhesive forces 937 00:24:54,789 --> 00:24:58,820 kind of force is called adhesive forces now depending on the intermolecular 938 00:24:58,820 --> 00:24:58,830 now depending on the intermolecular 939 00:24:58,830 --> 00:25:02,299 now depending on the intermolecular forces actually sometimes we have 940 00:25:02,299 --> 00:25:02,309 forces actually sometimes we have 941 00:25:02,309 --> 00:25:05,279 forces actually sometimes we have cohesive forces are greater than 942 00:25:05,279 --> 00:25:05,289 cohesive forces are greater than 943 00:25:05,289 --> 00:25:08,520 cohesive forces are greater than adhesive forces and sometimes adhesive 944 00:25:08,520 --> 00:25:08,530 adhesive forces and sometimes adhesive 945 00:25:08,530 --> 00:25:10,890 adhesive forces and sometimes adhesive forces are greater than cohesive forces 946 00:25:10,890 --> 00:25:10,900 forces are greater than cohesive forces 947 00:25:10,900 --> 00:25:14,640 forces are greater than cohesive forces now that results what we simply know as 948 00:25:14,640 --> 00:25:14,650 now that results what we simply know as 949 00:25:14,650 --> 00:25:19,500 now that results what we simply know as the capillary action of these liquids 950 00:25:19,500 --> 00:25:19,510 the capillary action of these liquids 951 00:25:19,510 --> 00:25:22,049 the capillary action of these liquids now what is a capillary action the 952 00:25:22,049 --> 00:25:22,059 now what is a capillary action the 953 00:25:22,059 --> 00:25:23,850 now what is a capillary action the capillary action is again as follow 954 00:25:23,850 --> 00:25:23,860 capillary action is again as follow 955 00:25:23,860 --> 00:25:27,930 capillary action is again as follow suppose that you have a liquid in a 956 00:25:27,930 --> 00:25:27,940 suppose that you have a liquid in a 957 00:25:27,940 --> 00:25:31,770 suppose that you have a liquid in a beaker right if you dip into that a very 958 00:25:31,770 --> 00:25:31,780 beaker right if you dip into that a very 959 00:25:31,780 --> 00:25:36,570 beaker right if you dip into that a very small diameter tube glass tube into that 960 00:25:36,570 --> 00:25:36,580 small diameter tube glass tube into that 961 00:25:36,580 --> 00:25:38,430 small diameter tube glass tube into that that's called the capillary actually and 962 00:25:38,430 --> 00:25:38,440 that's called the capillary actually and 963 00:25:38,440 --> 00:25:41,610 that's called the capillary actually and what you will see depending on whether 964 00:25:41,610 --> 00:25:41,620 what you will see depending on whether 965 00:25:41,620 --> 00:25:43,500 what you will see depending on whether the adhesive forces greater than 966 00:25:43,500 --> 00:25:43,510 the adhesive forces greater than 967 00:25:43,510 --> 00:25:44,520 the adhesive forces greater than cohesive or 968 00:25:44,520 --> 00:25:44,530 cohesive or 969 00:25:44,530 --> 00:25:47,250 cohesive or greater than adhesive you may have that 970 00:25:47,250 --> 00:25:47,260 greater than adhesive you may have that 971 00:25:47,260 --> 00:25:51,150 greater than adhesive you may have that the liquid will start rising up in that 972 00:25:51,150 --> 00:25:51,160 the liquid will start rising up in that 973 00:25:51,160 --> 00:25:54,330 the liquid will start rising up in that capillary tube or it may simply go down 974 00:25:54,330 --> 00:25:54,340 capillary tube or it may simply go down 975 00:25:54,340 --> 00:25:57,210 capillary tube or it may simply go down below the surface area in that capillary 976 00:25:57,210 --> 00:25:57,220 below the surface area in that capillary 977 00:25:57,220 --> 00:26:01,620 below the surface area in that capillary tube let's see how that is possible 978 00:26:01,620 --> 00:26:01,630 tube let's see how that is possible 979 00:26:01,630 --> 00:26:03,750 tube let's see how that is possible again this is what the capillary action 980 00:26:03,750 --> 00:26:03,760 again this is what the capillary action 981 00:26:03,760 --> 00:26:07,560 again this is what the capillary action here now we have water and the mercury 982 00:26:07,560 --> 00:26:07,570 here now we have water and the mercury 983 00:26:07,570 --> 00:26:10,860 here now we have water and the mercury again two liquids now in the water cases 984 00:26:10,860 --> 00:26:10,870 again two liquids now in the water cases 985 00:26:10,870 --> 00:26:15,210 again two liquids now in the water cases this surface is convex type that means 986 00:26:15,210 --> 00:26:15,220 this surface is convex type that means 987 00:26:15,220 --> 00:26:18,360 this surface is convex type that means like this fashion like this now here in 988 00:26:18,360 --> 00:26:18,370 like this fashion like this now here in 989 00:26:18,370 --> 00:26:22,440 like this fashion like this now here in the mercury it is convex concave type it 990 00:26:22,440 --> 00:26:22,450 the mercury it is convex concave type it 991 00:26:22,450 --> 00:26:26,820 the mercury it is convex concave type it is upwards like this now again in the 992 00:26:26,820 --> 00:26:26,830 is upwards like this now again in the 993 00:26:26,830 --> 00:26:32,190 is upwards like this now again in the water case the adhesive forces that 994 00:26:32,190 --> 00:26:32,200 water case the adhesive forces that 995 00:26:32,200 --> 00:26:34,160 water case the adhesive forces that means the attraction between water 996 00:26:34,160 --> 00:26:34,170 means the attraction between water 997 00:26:34,170 --> 00:26:38,010 means the attraction between water molecule and the glass surface which 998 00:26:38,010 --> 00:26:38,020 molecule and the glass surface which 999 00:26:38,020 --> 00:26:40,590 molecule and the glass surface which have also molecules there right is 1000 00:26:40,590 --> 00:26:40,600 have also molecules there right is 1001 00:26:40,600 --> 00:26:44,610 have also molecules there right is greater than the cohesive forces between 1002 00:26:44,610 --> 00:26:44,620 greater than the cohesive forces between 1003 00:26:44,620 --> 00:26:46,800 greater than the cohesive forces between two water molecules so what really 1004 00:26:46,800 --> 00:26:46,810 two water molecules so what really 1005 00:26:46,810 --> 00:26:51,630 two water molecules so what really happens because of this the water in 1006 00:26:51,630 --> 00:26:51,640 happens because of this the water in 1007 00:26:51,640 --> 00:26:56,400 happens because of this the water in fact try to increase the contact area 1008 00:26:56,400 --> 00:26:56,410 fact try to increase the contact area 1009 00:26:56,410 --> 00:27:00,060 fact try to increase the contact area with the glass because the more contact 1010 00:27:00,060 --> 00:27:00,070 with the glass because the more contact 1011 00:27:00,070 --> 00:27:02,700 with the glass because the more contact area between the water and the glass 1012 00:27:02,700 --> 00:27:02,710 area between the water and the glass 1013 00:27:02,710 --> 00:27:05,820 area between the water and the glass means stronger attractions and that also 1014 00:27:05,820 --> 00:27:05,830 means stronger attractions and that also 1015 00:27:05,830 --> 00:27:09,330 means stronger attractions and that also corresponds more stable system energy 1016 00:27:09,330 --> 00:27:09,340 corresponds more stable system energy 1017 00:27:09,340 --> 00:27:10,950 corresponds more stable system energy that will simply the energy will be 1018 00:27:10,950 --> 00:27:10,960 that will simply the energy will be 1019 00:27:10,960 --> 00:27:13,680 that will simply the energy will be lower in that case now on the other side 1020 00:27:13,680 --> 00:27:13,690 lower in that case now on the other side 1021 00:27:13,690 --> 00:27:18,560 lower in that case now on the other side over here in the mercury case so the 1022 00:27:18,560 --> 00:27:18,570 over here in the mercury case so the 1023 00:27:18,570 --> 00:27:20,880 over here in the mercury case so the cohesive forces that means the 1024 00:27:20,880 --> 00:27:20,890 cohesive forces that means the 1025 00:27:20,890 --> 00:27:23,490 cohesive forces that means the intermolecular force between the mercury 1026 00:27:23,490 --> 00:27:23,500 intermolecular force between the mercury 1027 00:27:23,500 --> 00:27:27,480 intermolecular force between the mercury atoms is much greater than the mercury 1028 00:27:27,480 --> 00:27:27,490 atoms is much greater than the mercury 1029 00:27:27,490 --> 00:27:29,970 atoms is much greater than the mercury and the glass molecules and that means 1030 00:27:29,970 --> 00:27:29,980 and the glass molecules and that means 1031 00:27:29,980 --> 00:27:33,630 and the glass molecules and that means that the mercury try to minimize the 1032 00:27:33,630 --> 00:27:33,640 that the mercury try to minimize the 1033 00:27:33,640 --> 00:27:36,210 that the mercury try to minimize the contact area with the glass and the 1034 00:27:36,210 --> 00:27:36,220 contact area with the glass and the 1035 00:27:36,220 --> 00:27:39,140 contact area with the glass and the mercury and that's why it has the 1036 00:27:39,140 --> 00:27:39,150 mercury and that's why it has the 1037 00:27:39,150 --> 00:27:42,210 mercury and that's why it has the concave type shape over here meniscus 1038 00:27:42,210 --> 00:27:42,220 concave type shape over here meniscus 1039 00:27:42,220 --> 00:27:43,740 concave type shape over here meniscus actually these are called the meniscus 1040 00:27:43,740 --> 00:27:43,750 actually these are called the meniscus 1041 00:27:43,750 --> 00:27:46,650 actually these are called the meniscus and that's what happens now what does 1042 00:27:46,650 --> 00:27:46,660 and that's what happens now what does 1043 00:27:46,660 --> 00:27:48,900 and that's what happens now what does that simply means again in capillary 1044 00:27:48,900 --> 00:27:48,910 that simply means again in capillary 1045 00:27:48,910 --> 00:27:51,870 that simply means again in capillary actions so if you have water here and 1046 00:27:51,870 --> 00:27:51,880 actions so if you have water here and 1047 00:27:51,880 --> 00:27:55,050 actions so if you have water here and the mercury here two liquids and if I 1048 00:27:55,050 --> 00:27:55,060 the mercury here two liquids and if I 1049 00:27:55,060 --> 00:27:58,380 the mercury here two liquids and if I dipped a capillary tube into the water 1050 00:27:58,380 --> 00:27:58,390 dipped a capillary tube into the water 1051 00:27:58,390 --> 00:28:00,870 dipped a capillary tube into the water again I will see that the water inside 1052 00:28:00,870 --> 00:28:00,880 again I will see that the water inside 1053 00:28:00,880 --> 00:28:03,510 again I will see that the water inside the capillary tube will rise up to a 1054 00:28:03,510 --> 00:28:03,520 the capillary tube will rise up to a 1055 00:28:03,520 --> 00:28:06,900 the capillary tube will rise up to a certain level right now in the case of 1056 00:28:06,900 --> 00:28:06,910 certain level right now in the case of 1057 00:28:06,910 --> 00:28:09,930 certain level right now in the case of mercury the inside the capillary the 1058 00:28:09,930 --> 00:28:09,940 mercury the inside the capillary the 1059 00:28:09,940 --> 00:28:13,050 mercury the inside the capillary the mercury level will go down right this is 1060 00:28:13,050 --> 00:28:13,060 mercury level will go down right this is 1061 00:28:13,060 --> 00:28:15,840 mercury level will go down right this is what is called the Kepler reaction and 1062 00:28:15,840 --> 00:28:15,850 what is called the Kepler reaction and 1063 00:28:15,850 --> 00:28:18,540 what is called the Kepler reaction and it's all again depends on the magnitude 1064 00:28:18,540 --> 00:28:18,550 it's all again depends on the magnitude 1065 00:28:18,550 --> 00:28:22,560 it's all again depends on the magnitude of adhesive versus cohesive forces 1066 00:28:22,560 --> 00:28:22,570 of adhesive versus cohesive forces 1067 00:28:22,570 --> 00:28:25,500 of adhesive versus cohesive forces adhesive and cohesive forces and it 1068 00:28:25,500 --> 00:28:25,510 adhesive and cohesive forces and it 1069 00:28:25,510 --> 00:28:28,490 adhesive and cohesive forces and it again depends on intermolecular forces 1070 00:28:28,490 --> 00:28:28,500 again depends on intermolecular forces 1071 00:28:28,500 --> 00:28:31,230 again depends on intermolecular forces again right usually if you have a very 1072 00:28:31,230 --> 00:28:31,240 again right usually if you have a very 1073 00:28:31,240 --> 00:28:34,910 again right usually if you have a very strong cohesive forces intermolecular 1074 00:28:34,910 --> 00:28:34,920 strong cohesive forces intermolecular 1075 00:28:34,920 --> 00:28:38,730 strong cohesive forces intermolecular attractions intermolecular forces in a 1076 00:28:38,730 --> 00:28:38,740 attractions intermolecular forces in a 1077 00:28:38,740 --> 00:28:42,020 attractions intermolecular forces in a liquid then it will behave like a 1078 00:28:42,020 --> 00:28:42,030 liquid then it will behave like a 1079 00:28:42,030 --> 00:28:45,060 liquid then it will behave like a mercury and again if the intermolecular 1080 00:28:45,060 --> 00:28:45,070 mercury and again if the intermolecular 1081 00:28:45,070 --> 00:28:46,650 mercury and again if the intermolecular forces are weak it will behave like 1082 00:28:46,650 --> 00:28:46,660 forces are weak it will behave like 1083 00:28:46,660 --> 00:28:50,490 forces are weak it will behave like again water but we should always compare 1084 00:28:50,490 --> 00:28:50,500 again water but we should always compare 1085 00:28:50,500 --> 00:28:53,610 again water but we should always compare it with the adhesive force adhesive 1086 00:28:53,610 --> 00:28:53,620 it with the adhesive force adhesive 1087 00:28:53,620 --> 00:28:55,470 it with the adhesive force adhesive force that means the liquid molecules 1088 00:28:55,470 --> 00:28:55,480 force that means the liquid molecules 1089 00:28:55,480 --> 00:28:59,850 force that means the liquid molecules and the surface of the container or the 1090 00:28:59,850 --> 00:28:59,860 and the surface of the container or the 1091 00:28:59,860 --> 00:29:05,010 and the surface of the container or the tables again okay now remember again all 1092 00:29:05,010 --> 00:29:05,020 tables again okay now remember again all 1093 00:29:05,020 --> 00:29:10,130 tables again okay now remember again all of these properties are also affected by 1094 00:29:10,130 --> 00:29:10,140 of these properties are also affected by 1095 00:29:10,140 --> 00:29:11,250 of these properties are also affected by temperature 1096 00:29:11,250 --> 00:29:11,260 temperature 1097 00:29:11,260 --> 00:29:14,550 temperature just like in viscosity here the 1098 00:29:14,550 --> 00:29:14,560 just like in viscosity here the 1099 00:29:14,560 --> 00:29:16,440 just like in viscosity here the capillary action is also affected by the 1100 00:29:16,440 --> 00:29:16,450 capillary action is also affected by the 1101 00:29:16,450 --> 00:29:25,260 capillary action is also affected by the temperature also okay now phase changes 1102 00:29:25,260 --> 00:29:25,270 temperature also okay now phase changes 1103 00:29:25,270 --> 00:29:30,600 temperature also okay now phase changes again is simply conversion from one 1104 00:29:30,600 --> 00:29:30,610 again is simply conversion from one 1105 00:29:30,610 --> 00:29:34,110 again is simply conversion from one state of matter to another is called 1106 00:29:34,110 --> 00:29:34,120 state of matter to another is called 1107 00:29:34,120 --> 00:29:35,910 state of matter to another is called phase change what does that means that 1108 00:29:35,910 --> 00:29:35,920 phase change what does that means that 1109 00:29:35,920 --> 00:29:41,610 phase change what does that means that means going from solid to liquid or from 1110 00:29:41,610 --> 00:29:41,620 means going from solid to liquid or from 1111 00:29:41,620 --> 00:29:45,510 means going from solid to liquid or from liquid to gas or just the other way 1112 00:29:45,510 --> 00:29:45,520 liquid to gas or just the other way 1113 00:29:45,520 --> 00:29:47,550 liquid to gas or just the other way around from gas to the liquid from 1114 00:29:47,550 --> 00:29:47,560 around from gas to the liquid from 1115 00:29:47,560 --> 00:29:50,130 around from gas to the liquid from liquid to the solid or solid to the gas 1116 00:29:50,130 --> 00:29:50,140 liquid to the solid or solid to the gas 1117 00:29:50,140 --> 00:29:53,520 liquid to the solid or solid to the gas gas to the solid are called phase 1118 00:29:53,520 --> 00:29:53,530 gas to the solid are called phase 1119 00:29:53,530 --> 00:29:57,660 gas to the solid are called phase changes so actually states here the 1120 00:29:57,660 --> 00:29:57,670 changes so actually states here the 1121 00:29:57,670 --> 00:30:00,120 changes so actually states here the state of the matter is called face the 1122 00:30:00,120 --> 00:30:00,130 state of the matter is called face the 1123 00:30:00,130 --> 00:30:01,920 state of the matter is called face the same things actually some kind of phase 1124 00:30:01,920 --> 00:30:01,930 same things actually some kind of phase 1125 00:30:01,930 --> 00:30:04,410 same things actually some kind of phase changes or state changes and so on now 1126 00:30:04,410 --> 00:30:04,420 changes or state changes and so on now 1127 00:30:04,420 --> 00:30:08,280 changes or state changes and so on now energy is either added or released in a 1128 00:30:08,280 --> 00:30:08,290 energy is either added or released in a 1129 00:30:08,290 --> 00:30:11,210 energy is either added or released in a phase change so we should know whether 1130 00:30:11,210 --> 00:30:11,220 phase change so we should know whether 1131 00:30:11,220 --> 00:30:19,220 phase change so we should know whether we are we're going to add energy or get 1132 00:30:19,220 --> 00:30:19,230 we are we're going to add energy or get 1133 00:30:19,230 --> 00:30:22,039 we are we're going to add energy or get energy from the phase changes in other 1134 00:30:22,039 --> 00:30:22,049 energy from the phase changes in other 1135 00:30:22,049 --> 00:30:24,260 energy from the phase changes in other words we have to know whether the 1136 00:30:24,260 --> 00:30:24,270 words we have to know whether the 1137 00:30:24,270 --> 00:30:26,830 words we have to know whether the process of phase change will be 1138 00:30:26,830 --> 00:30:26,840 process of phase change will be 1139 00:30:26,840 --> 00:30:31,460 process of phase change will be exothermic or endothermic right now we 1140 00:30:31,460 --> 00:30:31,470 exothermic or endothermic right now we 1141 00:30:31,470 --> 00:30:37,070 exothermic or endothermic right now we can actually guess that now phase 1142 00:30:37,070 --> 00:30:37,080 can actually guess that now phase 1143 00:30:37,080 --> 00:30:39,770 can actually guess that now phase changes Mountain freezing vaporize and 1144 00:30:39,770 --> 00:30:39,780 changes Mountain freezing vaporize and 1145 00:30:39,780 --> 00:30:42,740 changes Mountain freezing vaporize and condensed ins subliming deposit and 1146 00:30:42,740 --> 00:30:42,750 condensed ins subliming deposit and 1147 00:30:42,750 --> 00:30:45,110 condensed ins subliming deposit and these are the phase changes here are the 1148 00:30:45,110 --> 00:30:45,120 these are the phase changes here are the 1149 00:30:45,120 --> 00:30:48,020 these are the phase changes here are the definitions of those actually if you go 1150 00:30:48,020 --> 00:30:48,030 definitions of those actually if you go 1151 00:30:48,030 --> 00:30:51,890 definitions of those actually if you go from this is the liquid over here and 1152 00:30:51,890 --> 00:30:51,900 from this is the liquid over here and 1153 00:30:51,900 --> 00:30:56,090 from this is the liquid over here and this is the gas okay 1154 00:30:56,090 --> 00:30:56,100 this is the gas okay 1155 00:30:56,100 --> 00:30:59,590 this is the gas okay liquid and this is the solid and a gas 1156 00:30:59,590 --> 00:30:59,600 liquid and this is the solid and a gas 1157 00:30:59,600 --> 00:31:02,930 liquid and this is the solid and a gas between the liquid and the gas right 1158 00:31:02,930 --> 00:31:02,940 between the liquid and the gas right 1159 00:31:02,940 --> 00:31:06,049 between the liquid and the gas right here now if you go from liquid to the 1160 00:31:06,049 --> 00:31:06,059 here now if you go from liquid to the 1161 00:31:06,059 --> 00:31:09,919 here now if you go from liquid to the gas it's called vaporization now if you 1162 00:31:09,919 --> 00:31:09,929 gas it's called vaporization now if you 1163 00:31:09,929 --> 00:31:13,430 gas it's called vaporization now if you go from gas to the liquid it is called 1164 00:31:13,430 --> 00:31:13,440 go from gas to the liquid it is called 1165 00:31:13,440 --> 00:31:16,070 go from gas to the liquid it is called condensation which one is exothermic 1166 00:31:16,070 --> 00:31:16,080 condensation which one is exothermic 1167 00:31:16,080 --> 00:31:18,860 condensation which one is exothermic which one is endothermic vaporisation is 1168 00:31:18,860 --> 00:31:18,870 which one is endothermic vaporisation is 1169 00:31:18,870 --> 00:31:21,310 which one is endothermic vaporisation is what exothermic or endothermic 1170 00:31:21,310 --> 00:31:21,320 what exothermic or endothermic 1171 00:31:21,320 --> 00:31:24,620 what exothermic or endothermic endothermic now the from gas to the 1172 00:31:24,620 --> 00:31:24,630 endothermic now the from gas to the 1173 00:31:24,630 --> 00:31:28,279 endothermic now the from gas to the liquid condensation is exothermic right 1174 00:31:28,279 --> 00:31:28,289 liquid condensation is exothermic right 1175 00:31:28,289 --> 00:31:31,070 liquid condensation is exothermic right energy will be released or energy will 1176 00:31:31,070 --> 00:31:31,080 energy will be released or energy will 1177 00:31:31,080 --> 00:31:31,970 energy will be released or energy will be absorbed 1178 00:31:31,970 --> 00:31:31,980 be absorbed 1179 00:31:31,980 --> 00:31:35,270 be absorbed now here between the liquid and the 1180 00:31:35,270 --> 00:31:35,280 now here between the liquid and the 1181 00:31:35,280 --> 00:31:39,950 now here between the liquid and the solid we have freezing and melting or is 1182 00:31:39,950 --> 00:31:39,960 solid we have freezing and melting or is 1183 00:31:39,960 --> 00:31:42,020 solid we have freezing and melting or is called fusions the same things actually 1184 00:31:42,020 --> 00:31:42,030 called fusions the same things actually 1185 00:31:42,030 --> 00:31:44,810 called fusions the same things actually now if you go from solid to the liquid 1186 00:31:44,810 --> 00:31:44,820 now if you go from solid to the liquid 1187 00:31:44,820 --> 00:31:48,590 now if you go from solid to the liquid it will be endothermic process energy 1188 00:31:48,590 --> 00:31:48,600 it will be endothermic process energy 1189 00:31:48,600 --> 00:31:50,720 it will be endothermic process energy have to be absorbed now if you go from 1190 00:31:50,720 --> 00:31:50,730 have to be absorbed now if you go from 1191 00:31:50,730 --> 00:31:52,940 have to be absorbed now if you go from liquid to the solid freezing will be 1192 00:31:52,940 --> 00:31:52,950 liquid to the solid freezing will be 1193 00:31:52,950 --> 00:31:57,470 liquid to the solid freezing will be exothermic now then if you have gas to 1194 00:31:57,470 --> 00:31:57,480 exothermic now then if you have gas to 1195 00:31:57,480 --> 00:32:00,380 exothermic now then if you have gas to solid skip in the liquid phase that's 1196 00:32:00,380 --> 00:32:00,390 solid skip in the liquid phase that's 1197 00:32:00,390 --> 00:32:03,830 solid skip in the liquid phase that's called actually sublimation and the 1198 00:32:03,830 --> 00:32:03,840 called actually sublimation and the 1199 00:32:03,840 --> 00:32:06,020 called actually sublimation and the reverse of that is called depositions 1200 00:32:06,020 --> 00:32:06,030 reverse of that is called depositions 1201 00:32:06,030 --> 00:32:09,230 reverse of that is called depositions this is going to be actually exothermic 1202 00:32:09,230 --> 00:32:09,240 this is going to be actually exothermic 1203 00:32:09,240 --> 00:32:12,080 this is going to be actually exothermic and this is going to be endothermic 1204 00:32:12,080 --> 00:32:12,090 and this is going to be endothermic 1205 00:32:12,090 --> 00:32:17,409 and this is going to be endothermic process and the turbine process now okay 1206 00:32:17,409 --> 00:32:17,419 process and the turbine process now okay 1207 00:32:17,419 --> 00:32:23,750 process and the turbine process now okay let's look at the the energy change 1208 00:32:23,750 --> 00:32:23,760 let's look at the the energy change 1209 00:32:23,760 --> 00:32:28,220 let's look at the the energy change change of state actually and we said the 1210 00:32:28,220 --> 00:32:28,230 change of state actually and we said the 1211 00:32:28,230 --> 00:32:29,750 change of state actually and we said the process will be exothermic or 1212 00:32:29,750 --> 00:32:29,760 process will be exothermic or 1213 00:32:29,760 --> 00:32:32,750 process will be exothermic or endothermic now we're saying how about 1214 00:32:32,750 --> 00:32:32,760 endothermic now we're saying how about 1215 00:32:32,760 --> 00:32:35,690 endothermic now we're saying how about the amount of heat released or amount of 1216 00:32:35,690 --> 00:32:35,700 the amount of heat released or amount of 1217 00:32:35,700 --> 00:32:39,080 the amount of heat released or amount of heat absorbed and that corresponds to 1218 00:32:39,080 --> 00:32:39,090 heat absorbed and that corresponds to 1219 00:32:39,090 --> 00:32:41,450 heat absorbed and that corresponds to the energy changes here again 1220 00:32:41,450 --> 00:32:41,460 the energy changes here again 1221 00:32:41,460 --> 00:32:44,180 the energy changes here again we summarized it the heat of fusion is 1222 00:32:44,180 --> 00:32:44,190 we summarized it the heat of fusion is 1223 00:32:44,190 --> 00:32:46,760 we summarized it the heat of fusion is the energy required to change a solid 1224 00:32:46,760 --> 00:32:46,770 the energy required to change a solid 1225 00:32:46,770 --> 00:32:50,150 the energy required to change a solid that it is mountain point to a liquid 1226 00:32:50,150 --> 00:32:50,160 that it is mountain point to a liquid 1227 00:32:50,160 --> 00:32:53,510 that it is mountain point to a liquid now this is important right so when we 1228 00:32:53,510 --> 00:32:53,520 now this is important right so when we 1229 00:32:53,520 --> 00:32:56,360 now this is important right so when we talk about the heat of fusion of water 1230 00:32:56,360 --> 00:32:56,370 talk about the heat of fusion of water 1231 00:32:56,370 --> 00:33:01,520 talk about the heat of fusion of water and this may be actually specific heat 1232 00:33:01,520 --> 00:33:01,530 and this may be actually specific heat 1233 00:33:01,530 --> 00:33:06,350 and this may be actually specific heat of fusion type or molar heat of fusion 1234 00:33:06,350 --> 00:33:06,360 of fusion type or molar heat of fusion 1235 00:33:06,360 --> 00:33:09,230 of fusion type or molar heat of fusion type what is the molar heat of fusion 1236 00:33:09,230 --> 00:33:09,240 type what is the molar heat of fusion 1237 00:33:09,240 --> 00:33:11,750 type what is the molar heat of fusion type that simply means that the amount 1238 00:33:11,750 --> 00:33:11,760 type that simply means that the amount 1239 00:33:11,760 --> 00:33:16,730 type that simply means that the amount of heat actually required to melt 1 mole 1240 00:33:16,730 --> 00:33:16,740 of heat actually required to melt 1 mole 1241 00:33:16,740 --> 00:33:21,050 of heat actually required to melt 1 mole of ice to 1 mole of liquid at what 1242 00:33:21,050 --> 00:33:21,060 of ice to 1 mole of liquid at what 1243 00:33:21,060 --> 00:33:24,470 of ice to 1 mole of liquid at what temperature 0 degree centigrade melting 1244 00:33:24,470 --> 00:33:24,480 temperature 0 degree centigrade melting 1245 00:33:24,480 --> 00:33:27,200 temperature 0 degree centigrade melting point so we should remember that this is 1246 00:33:27,200 --> 00:33:27,210 point so we should remember that this is 1247 00:33:27,210 --> 00:33:29,630 point so we should remember that this is what it is at mountain point of the 1248 00:33:29,630 --> 00:33:29,640 what it is at mountain point of the 1249 00:33:29,640 --> 00:33:31,700 what it is at mountain point of the liquid actually or if you're talking 1250 00:33:31,700 --> 00:33:31,710 liquid actually or if you're talking 1251 00:33:31,710 --> 00:33:34,970 liquid actually or if you're talking about the specific heat of fusion that 1252 00:33:34,970 --> 00:33:34,980 about the specific heat of fusion that 1253 00:33:34,980 --> 00:33:39,590 about the specific heat of fusion that will be one gram of ice actually melting 1254 00:33:39,590 --> 00:33:39,600 will be one gram of ice actually melting 1255 00:33:39,600 --> 00:33:43,460 will be one gram of ice actually melting again at 0 degrees to have 0 degrees 1 1256 00:33:43,460 --> 00:33:43,470 again at 0 degrees to have 0 degrees 1 1257 00:33:43,470 --> 00:33:46,550 again at 0 degrees to have 0 degrees 1 gram water that is the specific heat but 1258 00:33:46,550 --> 00:33:46,560 gram water that is the specific heat but 1259 00:33:46,560 --> 00:33:49,910 gram water that is the specific heat but usually we use molar heat of fusion or 1260 00:33:49,910 --> 00:33:49,920 usually we use molar heat of fusion or 1261 00:33:49,920 --> 00:33:52,760 usually we use molar heat of fusion or molar heat of vaporization now the heat 1262 00:33:52,760 --> 00:33:52,770 molar heat of vaporization now the heat 1263 00:33:52,770 --> 00:33:54,650 molar heat of vaporization now the heat of vaporization is the energy required 1264 00:33:54,650 --> 00:33:54,660 of vaporization is the energy required 1265 00:33:54,660 --> 00:33:57,260 of vaporization is the energy required to change a liquid at it is boiling 1266 00:33:57,260 --> 00:33:57,270 to change a liquid at it is boiling 1267 00:33:57,270 --> 00:33:59,120 to change a liquid at it is boiling point to a gas that's and other things 1268 00:33:59,120 --> 00:33:59,130 point to a gas that's and other things 1269 00:33:59,130 --> 00:34:01,580 point to a gas that's and other things again when we talk about when we give 1270 00:34:01,580 --> 00:34:01,590 again when we talk about when we give 1271 00:34:01,590 --> 00:34:05,630 again when we talk about when we give you the molar heat of vaporization for 1272 00:34:05,630 --> 00:34:05,640 you the molar heat of vaporization for 1273 00:34:05,640 --> 00:34:08,600 you the molar heat of vaporization for water that means it is the amount of 1274 00:34:08,600 --> 00:34:08,610 water that means it is the amount of 1275 00:34:08,610 --> 00:34:12,379 water that means it is the amount of heat required to convert one mole of 1276 00:34:12,379 --> 00:34:12,389 heat required to convert one mole of 1277 00:34:12,389 --> 00:34:15,950 heat required to convert one mole of water at hundred degrees centigrade to 1278 00:34:15,950 --> 00:34:15,960 water at hundred degrees centigrade to 1279 00:34:15,960 --> 00:34:19,610 water at hundred degrees centigrade to one mole of gas vapor water at hundred 1280 00:34:19,610 --> 00:34:19,620 one mole of gas vapor water at hundred 1281 00:34:19,620 --> 00:34:22,129 one mole of gas vapor water at hundred degree centigrade but usually when we 1282 00:34:22,129 --> 00:34:22,139 degree centigrade but usually when we 1283 00:34:22,139 --> 00:34:24,649 degree centigrade but usually when we simply use this heat of vaporization or 1284 00:34:24,649 --> 00:34:24,659 simply use this heat of vaporization or 1285 00:34:24,659 --> 00:34:27,980 simply use this heat of vaporization or heat of fusion we don't really pay that 1286 00:34:27,980 --> 00:34:27,990 heat of fusion we don't really pay that 1287 00:34:27,990 --> 00:34:29,899 heat of fusion we don't really pay that much attention about the melting points 1288 00:34:29,899 --> 00:34:29,909 much attention about the melting points 1289 00:34:29,909 --> 00:34:33,740 much attention about the melting points or the boiling point sometimes we say 1290 00:34:33,740 --> 00:34:33,750 or the boiling point sometimes we say 1291 00:34:33,750 --> 00:34:34,800 or the boiling point sometimes we say the chain 1292 00:34:34,800 --> 00:34:34,810 the chain 1293 00:34:34,810 --> 00:34:37,830 the chain change of the heat of fusion or heat of 1294 00:34:37,830 --> 00:34:37,840 change of the heat of fusion or heat of 1295 00:34:37,840 --> 00:34:39,330 change of the heat of fusion or heat of vaporization with temperature is very 1296 00:34:39,330 --> 00:34:39,340 vaporization with temperature is very 1297 00:34:39,340 --> 00:34:41,040 vaporization with temperature is very small so we use that for all 1298 00:34:41,040 --> 00:34:41,050 small so we use that for all 1299 00:34:41,050 --> 00:34:42,960 small so we use that for all temperatures as a matter of fact or at 1300 00:34:42,960 --> 00:34:42,970 temperatures as a matter of fact or at 1301 00:34:42,970 --> 00:34:45,180 temperatures as a matter of fact or at least for certain range of temperatures 1302 00:34:45,180 --> 00:34:45,190 least for certain range of temperatures 1303 00:34:45,190 --> 00:34:47,520 least for certain range of temperatures now heat of sublimation is again the 1304 00:34:47,520 --> 00:34:47,530 now heat of sublimation is again the 1305 00:34:47,530 --> 00:34:49,920 now heat of sublimation is again the same changes of solid directly to the 1306 00:34:49,920 --> 00:34:49,930 same changes of solid directly to the 1307 00:34:49,930 --> 00:34:51,960 same changes of solid directly to the gas the same things again now if you 1308 00:34:51,960 --> 00:34:51,970 gas the same things again now if you 1309 00:34:51,970 --> 00:34:54,810 gas the same things again now if you have the reverse of these processes then 1310 00:34:54,810 --> 00:34:54,820 have the reverse of these processes then 1311 00:34:54,820 --> 00:34:56,790 have the reverse of these processes then the same amount of energy will be 1312 00:34:56,790 --> 00:34:56,800 the same amount of energy will be 1313 00:34:56,800 --> 00:35:00,300 the same amount of energy will be released to the surrounding again we 1314 00:35:00,300 --> 00:35:00,310 released to the surrounding again we 1315 00:35:00,310 --> 00:35:03,360 released to the surrounding again we have here heat of fusion heat of 1316 00:35:03,360 --> 00:35:03,370 have here heat of fusion heat of 1317 00:35:03,370 --> 00:35:05,730 have here heat of fusion heat of vaporization heat of sublimation for 1318 00:35:05,730 --> 00:35:05,740 vaporization heat of sublimation for 1319 00:35:05,740 --> 00:35:08,850 vaporization heat of sublimation for different molecules butane diethyl ether 1320 00:35:08,850 --> 00:35:08,860 different molecules butane diethyl ether 1321 00:35:08,860 --> 00:35:13,040 different molecules butane diethyl ether water and mercury now the question is 1322 00:35:13,040 --> 00:35:13,050 water and mercury now the question is 1323 00:35:13,050 --> 00:35:17,610 water and mercury now the question is what factor determines the magnitude of 1324 00:35:17,610 --> 00:35:17,620 what factor determines the magnitude of 1325 00:35:17,620 --> 00:35:22,350 what factor determines the magnitude of heat of fusion or heat of vaporization 1326 00:35:22,350 --> 00:35:22,360 heat of fusion or heat of vaporization 1327 00:35:22,360 --> 00:35:25,200 heat of fusion or heat of vaporization or heat of sublimation the main things 1328 00:35:25,200 --> 00:35:25,210 or heat of sublimation the main things 1329 00:35:25,210 --> 00:35:29,100 or heat of sublimation the main things is intermolecular forces that act in 1330 00:35:29,100 --> 00:35:29,110 is intermolecular forces that act in 1331 00:35:29,110 --> 00:35:31,410 is intermolecular forces that act in operating in that liquids or in that 1332 00:35:31,410 --> 00:35:31,420 operating in that liquids or in that 1333 00:35:31,420 --> 00:35:33,960 operating in that liquids or in that substance the higher the intermolecular 1334 00:35:33,960 --> 00:35:33,970 substance the higher the intermolecular 1335 00:35:33,970 --> 00:35:36,420 substance the higher the intermolecular forces I should say the stronger the 1336 00:35:36,420 --> 00:35:36,430 forces I should say the stronger the 1337 00:35:36,430 --> 00:35:38,700 forces I should say the stronger the intermolecular forces the higher will be 1338 00:35:38,700 --> 00:35:38,710 intermolecular forces the higher will be 1339 00:35:38,710 --> 00:35:42,750 intermolecular forces the higher will be the melting point or the and also the 1340 00:35:42,750 --> 00:35:42,760 the melting point or the and also the 1341 00:35:42,760 --> 00:35:44,910 the melting point or the and also the higher will be the heat of fusion and 1342 00:35:44,910 --> 00:35:44,920 higher will be the heat of fusion and 1343 00:35:44,920 --> 00:35:46,650 higher will be the heat of fusion and the higher will be the heat of 1344 00:35:46,650 --> 00:35:46,660 the higher will be the heat of 1345 00:35:46,660 --> 00:35:48,600 the higher will be the heat of vaporization high will be the heat of 1346 00:35:48,600 --> 00:35:48,610 vaporization high will be the heat of 1347 00:35:48,610 --> 00:35:51,710 vaporization high will be the heat of sublimation 's right so these are all 1348 00:35:51,710 --> 00:35:51,720 sublimation 's right so these are all 1349 00:35:51,720 --> 00:35:54,600 sublimation 's right so these are all determined by intermolecular forces 1350 00:35:54,600 --> 00:35:54,610 determined by intermolecular forces 1351 00:35:54,610 --> 00:35:58,520 determined by intermolecular forces because the stronger in fact forces 1352 00:35:58,520 --> 00:35:58,530 because the stronger in fact forces 1353 00:35:58,530 --> 00:36:01,080 because the stronger in fact forces acting between the molecules it will be 1354 00:36:01,080 --> 00:36:01,090 acting between the molecules it will be 1355 00:36:01,090 --> 00:36:05,040 acting between the molecules it will be more difficult to make it liquids from 1356 00:36:05,040 --> 00:36:05,050 more difficult to make it liquids from 1357 00:36:05,050 --> 00:36:06,510 more difficult to make it liquids from solid to liquid what does that means 1358 00:36:06,510 --> 00:36:06,520 solid to liquid what does that means 1359 00:36:06,520 --> 00:36:08,400 solid to liquid what does that means that means you have to give more energy 1360 00:36:08,400 --> 00:36:08,410 that means you have to give more energy 1361 00:36:08,410 --> 00:36:11,460 that means you have to give more energy and that means that these values heat of 1362 00:36:11,460 --> 00:36:11,470 and that means that these values heat of 1363 00:36:11,470 --> 00:36:13,260 and that means that these values heat of fusion heat of vaporization heat of 1364 00:36:13,260 --> 00:36:13,270 fusion heat of vaporization heat of 1365 00:36:13,270 --> 00:36:15,480 fusion heat of vaporization heat of sublimation will be higher you can 1366 00:36:15,480 --> 00:36:15,490 sublimation will be higher you can 1367 00:36:15,490 --> 00:36:18,030 sublimation will be higher you can actually compare these over here to in 1368 00:36:18,030 --> 00:36:18,040 actually compare these over here to in 1369 00:36:18,040 --> 00:36:19,740 actually compare these over here to in terms of intermolecular for example 1370 00:36:19,740 --> 00:36:19,750 terms of intermolecular for example 1371 00:36:19,750 --> 00:36:22,610 terms of intermolecular for example mercury has the strongest intermolecular 1372 00:36:22,610 --> 00:36:22,620 mercury has the strongest intermolecular 1373 00:36:22,620 --> 00:36:26,370 mercury has the strongest intermolecular forces and you see again all of these 1374 00:36:26,370 --> 00:36:26,380 forces and you see again all of these 1375 00:36:26,380 --> 00:36:28,770 forces and you see again all of these values are highest almost for the 1376 00:36:28,770 --> 00:36:28,780 values are highest almost for the 1377 00:36:28,780 --> 00:36:31,110 values are highest almost for the mercury than the water and continues 1378 00:36:31,110 --> 00:36:31,120 mercury than the water and continues 1379 00:36:31,120 --> 00:36:37,370 mercury than the water and continues like that now heating curves again are 1380 00:36:37,370 --> 00:36:37,380 like that now heating curves again are 1381 00:36:37,380 --> 00:36:45,350 like that now heating curves again are given simply the state of the substance 1382 00:36:45,350 --> 00:36:45,360 1383 00:36:45,360 --> 00:36:48,660 temperature and also versus the 1384 00:36:48,660 --> 00:36:48,670 temperature and also versus the 1385 00:36:48,670 --> 00:36:52,589 temperature and also versus the he added to that in other words for 1386 00:36:52,589 --> 00:36:52,599 he added to that in other words for 1387 00:36:52,599 --> 00:36:56,039 he added to that in other words for example let's consider the heating curve 1388 00:36:56,039 --> 00:36:56,049 example let's consider the heating curve 1389 00:36:56,049 --> 00:36:59,059 example let's consider the heating curve for water suppose this is for water and 1390 00:36:59,059 --> 00:36:59,069 for water suppose this is for water and 1391 00:36:59,069 --> 00:37:03,620 for water suppose this is for water and we take let's say 18 grams of water at 1392 00:37:03,620 --> 00:37:03,630 we take let's say 18 grams of water at 1393 00:37:03,630 --> 00:37:07,710 we take let's say 18 grams of water at minus 25 degrees centigrade let's say 18 1394 00:37:07,710 --> 00:37:07,720 minus 25 degrees centigrade let's say 18 1395 00:37:07,720 --> 00:37:11,760 minus 25 degrees centigrade let's say 18 grams becomes 1 mol of water at minus 25 1396 00:37:11,760 --> 00:37:11,770 grams becomes 1 mol of water at minus 25 1397 00:37:11,770 --> 00:37:13,289 grams becomes 1 mol of water at minus 25 degrees centigrade what does that mean 1398 00:37:13,289 --> 00:37:13,299 degrees centigrade what does that mean 1399 00:37:13,299 --> 00:37:15,270 degrees centigrade what does that mean that minus 25 degrees centigrade it is 1400 00:37:15,270 --> 00:37:15,280 that minus 25 degrees centigrade it is 1401 00:37:15,280 --> 00:37:20,030 that minus 25 degrees centigrade it is ice right solid so if you give heat to 1402 00:37:20,030 --> 00:37:20,040 ice right solid so if you give heat to 1403 00:37:20,040 --> 00:37:24,480 ice right solid so if you give heat to this one mole of water simply heat then 1404 00:37:24,480 --> 00:37:24,490 this one mole of water simply heat then 1405 00:37:24,490 --> 00:37:27,839 this one mole of water simply heat then the temperature will increase and until 1406 00:37:27,839 --> 00:37:27,849 the temperature will increase and until 1407 00:37:27,849 --> 00:37:30,690 the temperature will increase and until what until zero degrees centigrade over 1408 00:37:30,690 --> 00:37:30,700 what until zero degrees centigrade over 1409 00:37:30,700 --> 00:37:32,670 what until zero degrees centigrade over here zero degrees again is the melting 1410 00:37:32,670 --> 00:37:32,680 here zero degrees again is the melting 1411 00:37:32,680 --> 00:37:36,660 here zero degrees again is the melting point now then if you keep giving heat 1412 00:37:36,660 --> 00:37:36,670 point now then if you keep giving heat 1413 00:37:36,670 --> 00:37:41,220 point now then if you keep giving heat to that one mole of water zero degree 1414 00:37:41,220 --> 00:37:41,230 to that one mole of water zero degree 1415 00:37:41,230 --> 00:37:43,980 to that one mole of water zero degree centigrade ice actually then it will 1416 00:37:43,980 --> 00:37:43,990 centigrade ice actually then it will 1417 00:37:43,990 --> 00:37:48,030 centigrade ice actually then it will melt and at this point here it will be 1418 00:37:48,030 --> 00:37:48,040 melt and at this point here it will be 1419 00:37:48,040 --> 00:37:51,140 melt and at this point here it will be liquid water at zero degree centigrade 1420 00:37:51,140 --> 00:37:51,150 liquid water at zero degree centigrade 1421 00:37:51,150 --> 00:37:54,900 liquid water at zero degree centigrade again the amount of heat that given at 1422 00:37:54,900 --> 00:37:54,910 again the amount of heat that given at 1423 00:37:54,910 --> 00:38:00,240 again the amount of heat that given at zero degree centigrade to ice water is 1424 00:38:00,240 --> 00:38:00,250 zero degree centigrade to ice water is 1425 00:38:00,250 --> 00:38:03,930 zero degree centigrade to ice water is all used up to melt that water and the 1426 00:38:03,930 --> 00:38:03,940 all used up to melt that water and the 1427 00:38:03,940 --> 00:38:06,510 all used up to melt that water and the temperature does not change right the 1428 00:38:06,510 --> 00:38:06,520 temperature does not change right the 1429 00:38:06,520 --> 00:38:08,730 temperature does not change right the temperature does not change and then you 1430 00:38:08,730 --> 00:38:08,740 temperature does not change and then you 1431 00:38:08,740 --> 00:38:11,069 temperature does not change and then you simply from that point on when all of 1432 00:38:11,069 --> 00:38:11,079 simply from that point on when all of 1433 00:38:11,079 --> 00:38:14,190 simply from that point on when all of the simply ice is converted to the 1434 00:38:14,190 --> 00:38:14,200 the simply ice is converted to the 1435 00:38:14,200 --> 00:38:16,859 the simply ice is converted to the liquid water if you keep giving heat to 1436 00:38:16,859 --> 00:38:16,869 liquid water if you keep giving heat to 1437 00:38:16,869 --> 00:38:19,410 liquid water if you keep giving heat to that the temperature will increase the 1438 00:38:19,410 --> 00:38:19,420 that the temperature will increase the 1439 00:38:19,420 --> 00:38:20,760 that the temperature will increase the water temperature will increase increase 1440 00:38:20,760 --> 00:38:20,770 water temperature will increase increase 1441 00:38:20,770 --> 00:38:24,660 water temperature will increase increase until it reaches to the boiling point 1442 00:38:24,660 --> 00:38:24,670 until it reaches to the boiling point 1443 00:38:24,670 --> 00:38:26,700 until it reaches to the boiling point actually which is hundred degree 1444 00:38:26,700 --> 00:38:26,710 actually which is hundred degree 1445 00:38:26,710 --> 00:38:28,609 actually which is hundred degree centigrade under one atmosphere pressure 1446 00:38:28,609 --> 00:38:28,619 centigrade under one atmosphere pressure 1447 00:38:28,619 --> 00:38:32,010 centigrade under one atmosphere pressure atmospheric pressure and then when you 1448 00:38:32,010 --> 00:38:32,020 atmospheric pressure and then when you 1449 00:38:32,020 --> 00:38:34,770 atmospheric pressure and then when you reach there at this point the given 1450 00:38:34,770 --> 00:38:34,780 reach there at this point the given 1451 00:38:34,780 --> 00:38:37,079 reach there at this point the given amount of heat if you keep giving heat 1452 00:38:37,079 --> 00:38:37,089 amount of heat if you keep giving heat 1453 00:38:37,089 --> 00:38:40,170 amount of heat if you keep giving heat to the system will be used to evaporate 1454 00:38:40,170 --> 00:38:40,180 to the system will be used to evaporate 1455 00:38:40,180 --> 00:38:43,049 to the system will be used to evaporate that water to the gas and when you reach 1456 00:38:43,049 --> 00:38:43,059 that water to the gas and when you reach 1457 00:38:43,059 --> 00:38:47,430 that water to the gas and when you reach to point a here actually then all of the 1458 00:38:47,430 --> 00:38:47,440 to point a here actually then all of the 1459 00:38:47,440 --> 00:38:50,490 to point a here actually then all of the liquid will be in the form of vapor and 1460 00:38:50,490 --> 00:38:50,500 liquid will be in the form of vapor and 1461 00:38:50,500 --> 00:38:53,280 liquid will be in the form of vapor and if you keep keep giving heat to that 1462 00:38:53,280 --> 00:38:53,290 if you keep keep giving heat to that 1463 00:38:53,290 --> 00:38:55,559 if you keep keep giving heat to that then the temperature of that vapor gas 1464 00:38:55,559 --> 00:38:55,569 then the temperature of that vapor gas 1465 00:38:55,569 --> 00:38:58,500 then the temperature of that vapor gas water actually will increase as a matter 1466 00:38:58,500 --> 00:38:58,510 water actually will increase as a matter 1467 00:38:58,510 --> 00:39:01,260 water actually will increase as a matter of fact now if this is one 1468 00:39:01,260 --> 00:39:01,270 of fact now if this is one 1469 00:39:01,270 --> 00:39:04,680 of fact now if this is one moral of water for example this heat 1470 00:39:04,680 --> 00:39:04,690 moral of water for example this heat 1471 00:39:04,690 --> 00:39:08,490 moral of water for example this heat this amount of heat from B to C will be 1472 00:39:08,490 --> 00:39:08,500 this amount of heat from B to C will be 1473 00:39:08,500 --> 00:39:12,300 this amount of heat from B to C will be equal to the molar heat of fusion of 1474 00:39:12,300 --> 00:39:12,310 equal to the molar heat of fusion of 1475 00:39:12,310 --> 00:39:16,200 equal to the molar heat of fusion of water right molar of heat of fusion that 1476 00:39:16,200 --> 00:39:16,210 water right molar of heat of fusion that 1477 00:39:16,210 --> 00:39:18,660 water right molar of heat of fusion that means that the amount of heat must be 1478 00:39:18,660 --> 00:39:18,670 means that the amount of heat must be 1479 00:39:18,670 --> 00:39:21,270 means that the amount of heat must be given to one mole of ice at zero degree 1480 00:39:21,270 --> 00:39:21,280 given to one mole of ice at zero degree 1481 00:39:21,280 --> 00:39:23,250 given to one mole of ice at zero degree centigrade to convert that to one mole 1482 00:39:23,250 --> 00:39:23,260 centigrade to convert that to one mole 1483 00:39:23,260 --> 00:39:25,080 centigrade to convert that to one mole of water at zero degree centigrade now 1484 00:39:25,080 --> 00:39:25,090 of water at zero degree centigrade now 1485 00:39:25,090 --> 00:39:28,740 of water at zero degree centigrade now this amount over here again this heat 1486 00:39:28,740 --> 00:39:28,750 this amount over here again this heat 1487 00:39:28,750 --> 00:39:31,680 this amount over here again this heat from D to e actually corresponds to the 1488 00:39:31,680 --> 00:39:31,690 from D to e actually corresponds to the 1489 00:39:31,690 --> 00:39:34,320 from D to e actually corresponds to the molar heat of vaporization of water 1490 00:39:34,320 --> 00:39:34,330 molar heat of vaporization of water 1491 00:39:34,330 --> 00:39:36,810 molar heat of vaporization of water right as you see again molar heat of 1492 00:39:36,810 --> 00:39:36,820 right as you see again molar heat of 1493 00:39:36,820 --> 00:39:38,910 right as you see again molar heat of vaporization is always greater than this 1494 00:39:38,910 --> 00:39:38,920 vaporization is always greater than this 1495 00:39:38,920 --> 00:39:41,640 vaporization is always greater than this you can also calculate the amount of 1496 00:39:41,640 --> 00:39:41,650 you can also calculate the amount of 1497 00:39:41,650 --> 00:39:44,880 you can also calculate the amount of heat used to go from A to B using 1498 00:39:44,880 --> 00:39:44,890 heat used to go from A to B using 1499 00:39:44,890 --> 00:39:49,500 heat used to go from A to B using specific heat of ice actually and the 1500 00:39:49,500 --> 00:39:49,510 specific heat of ice actually and the 1501 00:39:49,510 --> 00:39:51,570 specific heat of ice actually and the amount of water and you can also 1502 00:39:51,570 --> 00:39:51,580 amount of water and you can also 1503 00:39:51,580 --> 00:39:53,910 amount of water and you can also calculate the heat given from C to e 1504 00:39:53,910 --> 00:39:53,920 calculate the heat given from C to e 1505 00:39:53,920 --> 00:39:56,370 calculate the heat given from C to e again by using specific heat of water 1506 00:39:56,370 --> 00:39:56,380 again by using specific heat of water 1507 00:39:56,380 --> 00:39:59,220 again by using specific heat of water and here by using the specific heat of 1508 00:39:59,220 --> 00:39:59,230 and here by using the specific heat of 1509 00:39:59,230 --> 00:40:02,190 and here by using the specific heat of gas you can calculate the amount of heat 1510 00:40:02,190 --> 00:40:02,200 gas you can calculate the amount of heat 1511 00:40:02,200 --> 00:40:04,470 gas you can calculate the amount of heat given to that system so this is called 1512 00:40:04,470 --> 00:40:04,480 given to that system so this is called 1513 00:40:04,480 --> 00:40:08,130 given to that system so this is called the heating curve and it can be done in 1514 00:40:08,130 --> 00:40:08,140 the heating curve and it can be done in 1515 00:40:08,140 --> 00:40:18,840 the heating curve and it can be done in fact for any substance now suppose that 1516 00:40:18,840 --> 00:40:18,850 fact for any substance now suppose that 1517 00:40:18,850 --> 00:40:28,290 fact for any substance now suppose that you have a vapor form of water in a 1518 00:40:28,290 --> 00:40:28,300 you have a vapor form of water in a 1519 00:40:28,300 --> 00:40:31,620 you have a vapor form of water in a container and suppose it's sent in a 1520 00:40:31,620 --> 00:40:31,630 container and suppose it's sent in a 1521 00:40:31,630 --> 00:40:35,690 container and suppose it's sent in a cylinder right which has a piston and 1522 00:40:35,690 --> 00:40:35,700 cylinder right which has a piston and 1523 00:40:35,700 --> 00:40:41,220 cylinder right which has a piston and suppose that the vapor is at hundred 1524 00:40:41,220 --> 00:40:41,230 suppose that the vapor is at hundred 1525 00:40:41,230 --> 00:40:43,500 suppose that the vapor is at hundred degrees and the pressure of the vapor is 1526 00:40:43,500 --> 00:40:43,510 degrees and the pressure of the vapor is 1527 00:40:43,510 --> 00:40:49,070 degrees and the pressure of the vapor is one atmosphere now if you simply 1528 00:40:49,070 --> 00:40:49,080 one atmosphere now if you simply 1529 00:40:49,080 --> 00:40:51,840 one atmosphere now if you simply increase the pressure by pushing the 1530 00:40:51,840 --> 00:40:51,850 increase the pressure by pushing the 1531 00:40:51,850 --> 00:40:54,660 increase the pressure by pushing the piston down on that water vapor at 1532 00:40:54,660 --> 00:40:54,670 piston down on that water vapor at 1533 00:40:54,670 --> 00:40:57,720 piston down on that water vapor at hundred degree centigrade what will 1534 00:40:57,720 --> 00:40:57,730 hundred degree centigrade what will 1535 00:40:57,730 --> 00:41:01,110 hundred degree centigrade what will happen the water will condense and we 1536 00:41:01,110 --> 00:41:01,120 happen the water will condense and we 1537 00:41:01,120 --> 00:41:06,450 happen the water will condense and we will have liquid waters now if you keep 1538 00:41:06,450 --> 00:41:06,460 will have liquid waters now if you keep 1539 00:41:06,460 --> 00:41:08,700 will have liquid waters now if you keep that piston there and increase now the 1540 00:41:08,700 --> 00:41:08,710 that piston there and increase now the 1541 00:41:08,710 --> 00:41:14,170 that piston there and increase now the temperature of the system then again 1542 00:41:14,170 --> 00:41:14,180 temperature of the system then again 1543 00:41:14,180 --> 00:41:17,740 temperature of the system then again that water actually condensed liquid 1544 00:41:17,740 --> 00:41:17,750 that water actually condensed liquid 1545 00:41:17,750 --> 00:41:20,440 that water actually condensed liquid water will be evaporated again you will 1546 00:41:20,440 --> 00:41:20,450 water will be evaporated again you will 1547 00:41:20,450 --> 00:41:22,330 water will be evaporated again you will have a gasp all gasp but now the 1548 00:41:22,330 --> 00:41:22,340 have a gasp all gasp but now the 1549 00:41:22,340 --> 00:41:24,820 have a gasp all gasp but now the pressure will be greater than one 1550 00:41:24,820 --> 00:41:24,830 pressure will be greater than one 1551 00:41:24,830 --> 00:41:27,310 pressure will be greater than one atmosphere right now if you increase the 1552 00:41:27,310 --> 00:41:27,320 atmosphere right now if you increase the 1553 00:41:27,320 --> 00:41:31,030 atmosphere right now if you increase the pressure again again you will have some 1554 00:41:31,030 --> 00:41:31,040 pressure again again you will have some 1555 00:41:31,040 --> 00:41:33,610 pressure again again you will have some liquid water forming and the gas and 1556 00:41:33,610 --> 00:41:33,620 liquid water forming and the gas and 1557 00:41:33,620 --> 00:41:37,390 liquid water forming and the gas and liquid water but now the pressure will 1558 00:41:37,390 --> 00:41:37,400 liquid water but now the pressure will 1559 00:41:37,400 --> 00:41:40,300 liquid water but now the pressure will be higher now if you increase the 1560 00:41:40,300 --> 00:41:40,310 be higher now if you increase the 1561 00:41:40,310 --> 00:41:43,680 be higher now if you increase the temperature again that condensed water 1562 00:41:43,680 --> 00:41:43,690 temperature again that condensed water 1563 00:41:43,690 --> 00:41:47,080 temperature again that condensed water will evaporate back and you'll law you 1564 00:41:47,080 --> 00:41:47,090 will evaporate back and you'll law you 1565 00:41:47,090 --> 00:41:49,390 will evaporate back and you'll law you will have in the cylinder all gaseous 1566 00:41:49,390 --> 00:41:49,400 will have in the cylinder all gaseous 1567 00:41:49,400 --> 00:41:54,840 will have in the cylinder all gaseous water now if you increase the pressure 1568 00:41:54,840 --> 00:41:54,850 water now if you increase the pressure 1569 00:41:54,850 --> 00:41:58,690 water now if you increase the pressure then you will still have liquid water 1570 00:41:58,690 --> 00:41:58,700 then you will still have liquid water 1571 00:41:58,700 --> 00:42:01,540 then you will still have liquid water liquid and the gas if you continue doing 1572 00:42:01,540 --> 00:42:01,550 liquid and the gas if you continue doing 1573 00:42:01,550 --> 00:42:04,930 liquid and the gas if you continue doing this increase in the pressure forming 1574 00:42:04,930 --> 00:42:04,940 this increase in the pressure forming 1575 00:42:04,940 --> 00:42:07,330 this increase in the pressure forming the liquid from the gas increase in the 1576 00:42:07,330 --> 00:42:07,340 the liquid from the gas increase in the 1577 00:42:07,340 --> 00:42:09,340 the liquid from the gas increase in the temperature evaporate in that liquid 1578 00:42:09,340 --> 00:42:09,350 temperature evaporate in that liquid 1579 00:42:09,350 --> 00:42:11,710 temperature evaporate in that liquid increase in pressure and so that you 1580 00:42:11,710 --> 00:42:11,720 increase in pressure and so that you 1581 00:42:11,720 --> 00:42:18,840 increase in pressure and so that you will reach to a temperature after which 1582 00:42:18,840 --> 00:42:18,850 will reach to a temperature after which 1583 00:42:18,850 --> 00:42:21,310 will reach to a temperature after which doesn't matter how much pressure we 1584 00:42:21,310 --> 00:42:21,320 doesn't matter how much pressure we 1585 00:42:21,320 --> 00:42:25,690 doesn't matter how much pressure we apply to the gaseous water vapor you 1586 00:42:25,690 --> 00:42:25,700 apply to the gaseous water vapor you 1587 00:42:25,700 --> 00:42:29,130 apply to the gaseous water vapor you will never able to get liquid water 1588 00:42:29,130 --> 00:42:29,140 will never able to get liquid water 1589 00:42:29,140 --> 00:42:33,190 will never able to get liquid water right liquid water and this temperature 1590 00:42:33,190 --> 00:42:33,200 right liquid water and this temperature 1591 00:42:33,200 --> 00:42:37,030 right liquid water and this temperature actually for water is about six hundred 1592 00:42:37,030 --> 00:42:37,040 actually for water is about six hundred 1593 00:42:37,040 --> 00:42:39,430 actually for water is about six hundred and forty seven point six degrees this 1594 00:42:39,430 --> 00:42:39,440 and forty seven point six degrees this 1595 00:42:39,440 --> 00:42:43,300 and forty seven point six degrees this corresponds to about 370 degree 1596 00:42:43,300 --> 00:42:43,310 corresponds to about 370 degree 1597 00:42:43,310 --> 00:42:46,120 corresponds to about 370 degree centigrade that means about that 1598 00:42:46,120 --> 00:42:46,130 centigrade that means about that 1599 00:42:46,130 --> 00:42:49,090 centigrade that means about that temperature doesn't matter how much 1600 00:42:49,090 --> 00:42:49,100 temperature doesn't matter how much 1601 00:42:49,100 --> 00:42:51,910 temperature doesn't matter how much pressure you apply to the gas you will 1602 00:42:51,910 --> 00:42:51,920 pressure you apply to the gas you will 1603 00:42:51,920 --> 00:42:55,870 pressure you apply to the gas you will never able to liquify it that means you 1604 00:42:55,870 --> 00:42:55,880 never able to liquify it that means you 1605 00:42:55,880 --> 00:42:58,060 never able to liquify it that means you won't get the liquid form of that 1606 00:42:58,060 --> 00:42:58,070 won't get the liquid form of that 1607 00:42:58,070 --> 00:43:01,090 won't get the liquid form of that compound now that temperature is called 1608 00:43:01,090 --> 00:43:01,100 compound now that temperature is called 1609 00:43:01,100 --> 00:43:04,030 compound now that temperature is called the critical temperature now the 1610 00:43:04,030 --> 00:43:04,040 the critical temperature now the 1611 00:43:04,040 --> 00:43:07,120 the critical temperature now the pressure at that temperature of the gas 1612 00:43:07,120 --> 00:43:07,130 pressure at that temperature of the gas 1613 00:43:07,130 --> 00:43:11,290 pressure at that temperature of the gas is called the critical pressure so every 1614 00:43:11,290 --> 00:43:11,300 is called the critical pressure so every 1615 00:43:11,300 --> 00:43:15,610 is called the critical pressure so every liquid has this simply liquid critical 1616 00:43:15,610 --> 00:43:15,620 liquid has this simply liquid critical 1617 00:43:15,620 --> 00:43:17,980 liquid has this simply liquid critical pressure and the critical temperature 1618 00:43:17,980 --> 00:43:17,990 pressure and the critical temperature 1619 00:43:17,990 --> 00:43:21,940 pressure and the critical temperature critical temperature now can we relate 1620 00:43:21,940 --> 00:43:21,950 critical temperature now can we relate 1621 00:43:21,950 --> 00:43:24,340 critical temperature now can we relate this critical temperature and critical 1622 00:43:24,340 --> 00:43:24,350 this critical temperature and critical 1623 00:43:24,350 --> 00:43:26,620 this critical temperature and critical pressure to the intermolecular forces 1624 00:43:26,620 --> 00:43:26,630 pressure to the intermolecular forces 1625 00:43:26,630 --> 00:43:27,310 pressure to the intermolecular forces yes 1626 00:43:27,310 --> 00:43:27,320 yes 1627 00:43:27,320 --> 00:43:30,280 yes the stronger the intermolecular forces 1628 00:43:30,280 --> 00:43:30,290 the stronger the intermolecular forces 1629 00:43:30,290 --> 00:43:33,220 the stronger the intermolecular forces that means higher will be the critical 1630 00:43:33,220 --> 00:43:33,230 that means higher will be the critical 1631 00:43:33,230 --> 00:43:36,490 that means higher will be the critical temperature and the critical pressure if 1632 00:43:36,490 --> 00:43:36,500 temperature and the critical pressure if 1633 00:43:36,500 --> 00:43:39,340 temperature and the critical pressure if you have weaker intermolecular forces 1634 00:43:39,340 --> 00:43:39,350 you have weaker intermolecular forces 1635 00:43:39,350 --> 00:43:41,020 you have weaker intermolecular forces than the critical pressure and 1636 00:43:41,020 --> 00:43:41,030 than the critical pressure and 1637 00:43:41,030 --> 00:43:44,110 than the critical pressure and relatively temperature will drop down so 1638 00:43:44,110 --> 00:43:44,120 relatively temperature will drop down so 1639 00:43:44,120 --> 00:43:46,960 relatively temperature will drop down so now if you go above the critical 1640 00:43:46,960 --> 00:43:46,970 now if you go above the critical 1641 00:43:46,970 --> 00:43:48,600 now if you go above the critical pressure and the critical temperature 1642 00:43:48,600 --> 00:43:48,610 pressure and the critical temperature 1643 00:43:48,610 --> 00:43:52,270 pressure and the critical temperature what we have there is supercritical 1644 00:43:52,270 --> 00:43:52,280 what we have there is supercritical 1645 00:43:52,280 --> 00:43:55,750 what we have there is supercritical fluids in other words you won't have a 1646 00:43:55,750 --> 00:43:55,760 fluids in other words you won't have a 1647 00:43:55,760 --> 00:44:00,610 fluids in other words you won't have a liquid you won't have a all gas but the 1648 00:44:00,610 --> 00:44:00,620 liquid you won't have a all gas but the 1649 00:44:00,620 --> 00:44:02,530 liquid you won't have a all gas but the state will be actually the substance 1650 00:44:02,530 --> 00:44:02,540 state will be actually the substance 1651 00:44:02,540 --> 00:44:06,090 state will be actually the substance will be sort of between liquid and a gas 1652 00:44:06,090 --> 00:44:06,100 will be sort of between liquid and a gas 1653 00:44:06,100 --> 00:44:09,040 will be sort of between liquid and a gas behaves like a liquid and behaves like a 1654 00:44:09,040 --> 00:44:09,050 behaves like a liquid and behaves like a 1655 00:44:09,050 --> 00:44:12,130 behaves like a liquid and behaves like a gas but there will be no phase 1656 00:44:12,130 --> 00:44:12,140 gas but there will be no phase 1657 00:44:12,140 --> 00:44:14,500 gas but there will be no phase boundaries like separations off the 1658 00:44:14,500 --> 00:44:14,510 boundaries like separations off the 1659 00:44:14,510 --> 00:44:16,660 boundaries like separations off the phases like liquid or gas and this is 1660 00:44:16,660 --> 00:44:16,670 phases like liquid or gas and this is 1661 00:44:16,670 --> 00:44:18,760 phases like liquid or gas and this is simply called supercritical fluids and 1662 00:44:18,760 --> 00:44:18,770 simply called supercritical fluids and 1663 00:44:18,770 --> 00:44:21,220 simply called supercritical fluids and it is very very useful in chemistry 1664 00:44:21,220 --> 00:44:21,230 it is very very useful in chemistry 1665 00:44:21,230 --> 00:44:24,820 it is very very useful in chemistry sometimes to use that as a solvent to 1666 00:44:24,820 --> 00:44:24,830 sometimes to use that as a solvent to 1667 00:44:24,830 --> 00:44:27,610 sometimes to use that as a solvent to carry out certain separations and 1668 00:44:27,610 --> 00:44:27,620 carry out certain separations and 1669 00:44:27,620 --> 00:44:33,370 carry out certain separations and reactions and so on ok now this gives 1670 00:44:33,370 --> 00:44:33,380 reactions and so on ok now this gives 1671 00:44:33,380 --> 00:44:36,820 reactions and so on ok now this gives you again the critical temperature of 1672 00:44:36,820 --> 00:44:36,830 you again the critical temperature of 1673 00:44:36,830 --> 00:44:39,790 you again the critical temperature of the substances and the corresponding 1674 00:44:39,790 --> 00:44:39,800 the substances and the corresponding 1675 00:44:39,800 --> 00:44:42,400 the substances and the corresponding critical pressures again if you compare 1676 00:44:42,400 --> 00:44:42,410 critical pressures again if you compare 1677 00:44:42,410 --> 00:44:44,920 critical pressures again if you compare these values this increases as you go 1678 00:44:44,920 --> 00:44:44,930 these values this increases as you go 1679 00:44:44,930 --> 00:44:47,820 these values this increases as you go down and again the intermolecular forces 1680 00:44:47,820 --> 00:44:47,830 down and again the intermolecular forces 1681 00:44:47,830 --> 00:44:50,890 down and again the intermolecular forces actually increases as we go down the 1682 00:44:50,890 --> 00:44:50,900 actually increases as we go down the 1683 00:44:50,900 --> 00:44:53,020 actually increases as we go down the Grieg of attraction intermolecular 1684 00:44:53,020 --> 00:44:53,030 Grieg of attraction intermolecular 1685 00:44:53,030 --> 00:44:55,990 Grieg of attraction intermolecular attractions increases as we go down and 1686 00:44:55,990 --> 00:44:56,000 attractions increases as we go down and 1687 00:44:56,000 --> 00:44:58,270 attractions increases as we go down and this is reflected in the critical 1688 00:44:58,270 --> 00:44:58,280 this is reflected in the critical 1689 00:44:58,280 --> 00:45:02,800 this is reflected in the critical temperature and critical pressure now 1690 00:45:02,800 --> 00:45:02,810 temperature and critical pressure now 1691 00:45:02,810 --> 00:45:06,900 temperature and critical pressure now our vapor pressure okay I guess I can 1692 00:45:06,900 --> 00:45:06,910 our vapor pressure okay I guess I can 1693 00:45:06,910 --> 00:45:11,680 our vapor pressure okay I guess I can let's say we try to explain this vapor 1694 00:45:11,680 --> 00:45:11,690 let's say we try to explain this vapor 1695 00:45:11,690 --> 00:45:19,480 let's say we try to explain this vapor pressure of liquids 1696 00:45:19,480 --> 00:45:19,490 1697 00:45:19,490 --> 00:45:26,589 now this thesis simply gives you the 1698 00:45:26,589 --> 00:45:26,599 now this thesis simply gives you the 1699 00:45:26,599 --> 00:45:29,839 now this thesis simply gives you the distribution of the kinetic energy among 1700 00:45:29,839 --> 00:45:29,849 distribution of the kinetic energy among 1701 00:45:29,849 --> 00:45:35,120 distribution of the kinetic energy among the molecules in the liquid and in the 1702 00:45:35,120 --> 00:45:35,130 the molecules in the liquid and in the 1703 00:45:35,130 --> 00:45:37,099 the molecules in the liquid and in the gas also it's very similar like this 1704 00:45:37,099 --> 00:45:37,109 gas also it's very similar like this 1705 00:45:37,109 --> 00:45:39,470 gas also it's very similar like this this shows number of molecules this is 1706 00:45:39,470 --> 00:45:39,480 this shows number of molecules this is 1707 00:45:39,480 --> 00:45:41,630 this shows number of molecules this is kinetic energy and what did that means 1708 00:45:41,630 --> 00:45:41,640 kinetic energy and what did that means 1709 00:45:41,640 --> 00:45:43,849 kinetic energy and what did that means for example the number of molecules 1710 00:45:43,849 --> 00:45:43,859 for example the number of molecules 1711 00:45:43,859 --> 00:45:45,740 for example the number of molecules which have kinetic energy this value 1712 00:45:45,740 --> 00:45:45,750 which have kinetic energy this value 1713 00:45:45,750 --> 00:45:48,170 which have kinetic energy this value will be equal to that and this value 1714 00:45:48,170 --> 00:45:48,180 will be equal to that and this value 1715 00:45:48,180 --> 00:45:49,970 will be equal to that and this value will be equal to that so again you see 1716 00:45:49,970 --> 00:45:49,980 will be equal to that so again you see 1717 00:45:49,980 --> 00:45:51,890 will be equal to that so again you see the number of molecules which have the 1718 00:45:51,890 --> 00:45:51,900 the number of molecules which have the 1719 00:45:51,900 --> 00:45:54,529 the number of molecules which have the kinetic energy this correspondent to the 1720 00:45:54,529 --> 00:45:54,539 kinetic energy this correspondent to the 1721 00:45:54,539 --> 00:45:57,079 kinetic energy this correspondent to the maximum will probably the highest number 1722 00:45:57,079 --> 00:45:57,089 maximum will probably the highest number 1723 00:45:57,089 --> 00:45:59,270 maximum will probably the highest number highest number and so on and some 1724 00:45:59,270 --> 00:45:59,280 highest number and so on and some 1725 00:45:59,280 --> 00:46:00,950 highest number and so on and some molecules will have very high kinetic 1726 00:46:00,950 --> 00:46:00,960 molecules will have very high kinetic 1727 00:46:00,960 --> 00:46:02,750 molecules will have very high kinetic energy some molecules will be low 1728 00:46:02,750 --> 00:46:02,760 energy some molecules will be low 1729 00:46:02,760 --> 00:46:04,730 energy some molecules will be low kinetic energy some will be sort of 1730 00:46:04,730 --> 00:46:04,740 kinetic energy some will be sort of 1731 00:46:04,740 --> 00:46:07,579 kinetic energy some will be sort of intermediate now if you increase the 1732 00:46:07,579 --> 00:46:07,589 intermediate now if you increase the 1733 00:46:07,589 --> 00:46:10,670 intermediate now if you increase the temperature what happens the average 1734 00:46:10,670 --> 00:46:10,680 temperature what happens the average 1735 00:46:10,680 --> 00:46:12,950 temperature what happens the average kinetic energy increases you see the 1736 00:46:12,950 --> 00:46:12,960 kinetic energy increases you see the 1737 00:46:12,960 --> 00:46:14,809 kinetic energy increases you see the shape of the curve would look like this 1738 00:46:14,809 --> 00:46:14,819 shape of the curve would look like this 1739 00:46:14,819 --> 00:46:16,700 shape of the curve would look like this what does that means that means that the 1740 00:46:16,700 --> 00:46:16,710 what does that means that means that the 1741 00:46:16,710 --> 00:46:18,950 what does that means that means that the average kinetic energy of the molecules 1742 00:46:18,950 --> 00:46:18,960 average kinetic energy of the molecules 1743 00:46:18,960 --> 00:46:20,450 average kinetic energy of the molecules at higher temperatures will be higher 1744 00:46:20,450 --> 00:46:20,460 at higher temperatures will be higher 1745 00:46:20,460 --> 00:46:22,700 at higher temperatures will be higher than the average kinetic energy at lower 1746 00:46:22,700 --> 00:46:22,710 than the average kinetic energy at lower 1747 00:46:22,710 --> 00:46:25,700 than the average kinetic energy at lower temperatures actually this is lower than 1748 00:46:25,700 --> 00:46:25,710 temperatures actually this is lower than 1749 00:46:25,710 --> 00:46:28,430 temperatures actually this is lower than that again so that is how the kinetic 1750 00:46:28,430 --> 00:46:28,440 that again so that is how the kinetic 1751 00:46:28,440 --> 00:46:29,630 that again so that is how the kinetic energy distribution is among the 1752 00:46:29,630 --> 00:46:29,640 energy distribution is among the 1753 00:46:29,640 --> 00:46:32,150 energy distribution is among the molecules in the liquid and it's also in 1754 00:46:32,150 --> 00:46:32,160 molecules in the liquid and it's also in 1755 00:46:32,160 --> 00:46:34,069 molecules in the liquid and it's also in a gas or base a little bit different 1756 00:46:34,069 --> 00:46:34,079 a gas or base a little bit different 1757 00:46:34,079 --> 00:46:37,660 a gas or base a little bit different shape but very similar shape lines okay 1758 00:46:37,660 --> 00:46:37,670 shape but very similar shape lines okay 1759 00:46:37,670 --> 00:46:46,460 shape but very similar shape lines okay now suppose that I have a beaker and I 1760 00:46:46,460 --> 00:46:46,470 now suppose that I have a beaker and I 1761 00:46:46,470 --> 00:46:54,710 now suppose that I have a beaker and I put water on it just water this is 1762 00:46:54,710 --> 00:46:54,720 put water on it just water this is 1763 00:46:54,720 --> 00:47:00,319 put water on it just water this is liquid water right like this and now if 1764 00:47:00,319 --> 00:47:00,329 liquid water right like this and now if 1765 00:47:00,329 --> 00:47:03,410 liquid water right like this and now if I have that and put it there that much 1766 00:47:03,410 --> 00:47:03,420 I have that and put it there that much 1767 00:47:03,420 --> 00:47:07,940 I have that and put it there that much water it half-full and come back after 1768 00:47:07,940 --> 00:47:07,950 water it half-full and come back after 1769 00:47:07,950 --> 00:47:16,030 water it half-full and come back after about a week or so what will happen 1770 00:47:16,030 --> 00:47:16,040 1771 00:47:16,040 --> 00:47:24,260 let's say ten days later one month okay 1772 00:47:24,260 --> 00:47:24,270 let's say ten days later one month okay 1773 00:47:24,270 --> 00:47:27,370 let's say ten days later one month okay that means all of those will evaporate 1774 00:47:27,370 --> 00:47:27,380 that means all of those will evaporate 1775 00:47:27,380 --> 00:47:31,940 that means all of those will evaporate right we'll go from gases to the liquid 1776 00:47:31,940 --> 00:47:31,950 right we'll go from gases to the liquid 1777 00:47:31,950 --> 00:47:34,340 right we'll go from gases to the liquid to the gaseous state evaporate but 1778 00:47:34,340 --> 00:47:34,350 to the gaseous state evaporate but 1779 00:47:34,350 --> 00:47:39,410 to the gaseous state evaporate but suppose that I have liquid in a beaker 1780 00:47:39,410 --> 00:47:39,420 suppose that I have liquid in a beaker 1781 00:47:39,420 --> 00:47:43,070 suppose that I have liquid in a beaker like this water let's say now I put it 1782 00:47:43,070 --> 00:47:43,080 like this water let's say now I put it 1783 00:47:43,080 --> 00:47:47,530 like this water let's say now I put it on a table here then I put a jar on it 1784 00:47:47,530 --> 00:47:47,540 on a table here then I put a jar on it 1785 00:47:47,540 --> 00:47:53,830 on a table here then I put a jar on it like this a glass jar dumbbell shape 1786 00:47:53,830 --> 00:47:53,840 like this a glass jar dumbbell shape 1787 00:47:53,840 --> 00:47:57,950 like this a glass jar dumbbell shape that means I close it this is the glass 1788 00:47:57,950 --> 00:47:57,960 that means I close it this is the glass 1789 00:47:57,960 --> 00:48:02,750 that means I close it this is the glass again jar put it on that and suppose 1790 00:48:02,750 --> 00:48:02,760 again jar put it on that and suppose 1791 00:48:02,760 --> 00:48:07,760 again jar put it on that and suppose that again I have no water gaseous water 1792 00:48:07,760 --> 00:48:07,770 that again I have no water gaseous water 1793 00:48:07,770 --> 00:48:10,300 that again I have no water gaseous water molecules here you can assume that 1794 00:48:10,300 --> 00:48:10,310 molecules here you can assume that 1795 00:48:10,310 --> 00:48:13,190 molecules here you can assume that vacuum there or but doesn't have to be 1796 00:48:13,190 --> 00:48:13,200 vacuum there or but doesn't have to be 1797 00:48:13,200 --> 00:48:14,810 vacuum there or but doesn't have to be vacuum but just say that there's no 1798 00:48:14,810 --> 00:48:14,820 vacuum but just say that there's no 1799 00:48:14,820 --> 00:48:18,980 vacuum but just say that there's no water there then if I come back about 1800 00:48:18,980 --> 00:48:18,990 water there then if I come back about 1801 00:48:18,990 --> 00:48:21,950 water there then if I come back about two days later what will happen if the 1802 00:48:21,950 --> 00:48:21,960 two days later what will happen if the 1803 00:48:21,960 --> 00:48:29,290 two days later what will happen if the temperatures are the same 1804 00:48:29,290 --> 00:48:29,300 1805 00:48:29,300 --> 00:48:32,450 actually the level here will go a little 1806 00:48:32,450 --> 00:48:32,460 actually the level here will go a little 1807 00:48:32,460 --> 00:48:34,880 actually the level here will go a little bit downward now if I come about ten 1808 00:48:34,880 --> 00:48:34,890 bit downward now if I come about ten 1809 00:48:34,890 --> 00:48:39,470 bit downward now if I come about ten days 15 days and then we'll still be the 1810 00:48:39,470 --> 00:48:39,480 days 15 days and then we'll still be the 1811 00:48:39,480 --> 00:48:42,650 days 15 days and then we'll still be the same if it is sealed again that means 1812 00:48:42,650 --> 00:48:42,660 same if it is sealed again that means 1813 00:48:42,660 --> 00:48:44,270 same if it is sealed again that means it's closed and the temperature is the 1814 00:48:44,270 --> 00:48:44,280 it's closed and the temperature is the 1815 00:48:44,280 --> 00:48:47,510 it's closed and the temperature is the same around surrounding temperature is 1816 00:48:47,510 --> 00:48:47,520 same around surrounding temperature is 1817 00:48:47,520 --> 00:48:51,710 same around surrounding temperature is the same that means they will there will 1818 00:48:51,710 --> 00:48:51,720 the same that means they will there will 1819 00:48:51,720 --> 00:48:56,510 the same that means they will there will be water in that beaker forever as long 1820 00:48:56,510 --> 00:48:56,520 be water in that beaker forever as long 1821 00:48:56,520 --> 00:48:57,890 be water in that beaker forever as long as the temperature is the same as long 1822 00:48:57,890 --> 00:48:57,900 as the temperature is the same as long 1823 00:48:57,900 --> 00:49:00,770 as the temperature is the same as long as the system is sealed right now let's 1824 00:49:00,770 --> 00:49:00,780 as the system is sealed right now let's 1825 00:49:00,780 --> 00:49:02,810 as the system is sealed right now let's try to examine what is really going on 1826 00:49:02,810 --> 00:49:02,820 try to examine what is really going on 1827 00:49:02,820 --> 00:49:06,080 try to examine what is really going on why when it's open there will be no 1828 00:49:06,080 --> 00:49:06,090 why when it's open there will be no 1829 00:49:06,090 --> 00:49:09,080 why when it's open there will be no water after a certain time but if it is 1830 00:49:09,080 --> 00:49:09,090 water after a certain time but if it is 1831 00:49:09,090 --> 00:49:12,410 water after a certain time but if it is closed seal the same temperature but 1832 00:49:12,410 --> 00:49:12,420 closed seal the same temperature but 1833 00:49:12,420 --> 00:49:16,630 closed seal the same temperature but there will always be water there now 1834 00:49:16,630 --> 00:49:16,640 there will always be water there now 1835 00:49:16,640 --> 00:49:20,720 there will always be water there now what really happens is this let's 1836 00:49:20,720 --> 00:49:20,730 what really happens is this let's 1837 00:49:20,730 --> 00:49:25,840 what really happens is this let's consider the molecules at the surface 1838 00:49:25,840 --> 00:49:25,850 consider the molecules at the surface 1839 00:49:25,850 --> 00:49:30,230 consider the molecules at the surface right so remember again some of the 1840 00:49:30,230 --> 00:49:30,240 right so remember again some of the 1841 00:49:30,240 --> 00:49:33,700 right so remember again some of the molecules again at the surface if you 1842 00:49:33,700 --> 00:49:33,710 molecules again at the surface if you 1843 00:49:33,710 --> 00:49:39,830 molecules again at the surface if you simply look at consider the the kinetic 1844 00:49:39,830 --> 00:49:39,840 simply look at consider the the kinetic 1845 00:49:39,840 --> 00:49:42,080 simply look at consider the the kinetic energy distributions among the molecules 1846 00:49:42,080 --> 00:49:42,090 energy distributions among the molecules 1847 00:49:42,090 --> 00:49:44,660 energy distributions among the molecules at the surface right it would be 1848 00:49:44,660 --> 00:49:44,670 at the surface right it would be 1849 00:49:44,670 --> 00:49:47,060 at the surface right it would be something like this at this temperature 1850 00:49:47,060 --> 00:49:47,070 something like this at this temperature 1851 00:49:47,070 --> 00:49:52,480 something like this at this temperature for example something like that now the 1852 00:49:52,480 --> 00:49:52,490 for example something like that now the 1853 00:49:52,490 --> 00:49:55,010 for example something like that now the molecules water molecules or the liquid 1854 00:49:55,010 --> 00:49:55,020 molecules water molecules or the liquid 1855 00:49:55,020 --> 00:49:56,930 molecules water molecules or the liquid molecules whatever that is and let's say 1856 00:49:56,930 --> 00:49:56,940 molecules whatever that is and let's say 1857 00:49:56,940 --> 00:49:59,030 molecules whatever that is and let's say water molecules stays in the liquid form 1858 00:49:59,030 --> 00:49:59,040 water molecules stays in the liquid form 1859 00:49:59,040 --> 00:50:02,360 water molecules stays in the liquid form why because they are attracted by the 1860 00:50:02,360 --> 00:50:02,370 why because they are attracted by the 1861 00:50:02,370 --> 00:50:07,130 why because they are attracted by the other water molecules right that's why 1862 00:50:07,130 --> 00:50:07,140 other water molecules right that's why 1863 00:50:07,140 --> 00:50:08,990 other water molecules right that's why they're simply staying in water in the 1864 00:50:08,990 --> 00:50:09,000 they're simply staying in water in the 1865 00:50:09,000 --> 00:50:09,770 they're simply staying in water in the liquid phase 1866 00:50:09,770 --> 00:50:09,780 liquid phase 1867 00:50:09,780 --> 00:50:12,950 liquid phase but suppose that some of the water 1868 00:50:12,950 --> 00:50:12,960 but suppose that some of the water 1869 00:50:12,960 --> 00:50:15,830 but suppose that some of the water molecules that the surface has very high 1870 00:50:15,830 --> 00:50:15,840 molecules that the surface has very high 1871 00:50:15,840 --> 00:50:17,660 molecules that the surface has very high kinetic energy much higher than the 1872 00:50:17,660 --> 00:50:17,670 kinetic energy much higher than the 1873 00:50:17,670 --> 00:50:19,700 kinetic energy much higher than the average kinetic energy is that possible 1874 00:50:19,700 --> 00:50:19,710 average kinetic energy is that possible 1875 00:50:19,710 --> 00:50:21,830 average kinetic energy is that possible sure that would be less number of 1876 00:50:21,830 --> 00:50:21,840 sure that would be less number of 1877 00:50:21,840 --> 00:50:23,570 sure that would be less number of molecules but there will be molecules 1878 00:50:23,570 --> 00:50:23,580 molecules but there will be molecules 1879 00:50:23,580 --> 00:50:26,480 molecules but there will be molecules that have kinetic energy large now if 1880 00:50:26,480 --> 00:50:26,490 that have kinetic energy large now if 1881 00:50:26,490 --> 00:50:29,750 that have kinetic energy large now if this kinetic energy large enough to make 1882 00:50:29,750 --> 00:50:29,760 this kinetic energy large enough to make 1883 00:50:29,760 --> 00:50:32,600 this kinetic energy large enough to make the molecule water molecule break the 1884 00:50:32,600 --> 00:50:32,610 the molecule water molecule break the 1885 00:50:32,610 --> 00:50:34,700 the molecule water molecule break the attraction forces between the liquid and 1886 00:50:34,700 --> 00:50:34,710 attraction forces between the liquid and 1887 00:50:34,710 --> 00:50:37,640 attraction forces between the liquid and the liquid and that molecule will go 1888 00:50:37,640 --> 00:50:37,650 the liquid and that molecule will go 1889 00:50:37,650 --> 00:50:39,590 the liquid and that molecule will go from the liquid state into the gaseous 1890 00:50:39,590 --> 00:50:39,600 from the liquid state into the gaseous 1891 00:50:39,600 --> 00:50:40,110 from the liquid state into the gaseous state 1892 00:50:40,110 --> 00:50:40,120 state 1893 00:50:40,120 --> 00:50:42,540 state right it will escape and then we'll go 1894 00:50:42,540 --> 00:50:42,550 right it will escape and then we'll go 1895 00:50:42,550 --> 00:50:48,920 right it will escape and then we'll go into the liquid state likeness now again 1896 00:50:48,920 --> 00:50:48,930 into the liquid state likeness now again 1897 00:50:48,930 --> 00:50:54,240 into the liquid state likeness now again the kinetic energy distributions of the 1898 00:50:54,240 --> 00:50:54,250 the kinetic energy distributions of the 1899 00:50:54,250 --> 00:50:55,830 the kinetic energy distributions of the molecule at the surface will never 1900 00:50:55,830 --> 00:50:55,840 molecule at the surface will never 1901 00:50:55,840 --> 00:50:57,360 molecule at the surface will never change as long as the temperature is the 1902 00:50:57,360 --> 00:50:57,370 change as long as the temperature is the 1903 00:50:57,370 --> 00:51:00,180 change as long as the temperature is the same because when one molecule at high 1904 00:51:00,180 --> 00:51:00,190 same because when one molecule at high 1905 00:51:00,190 --> 00:51:03,480 same because when one molecule at high high kinetic energy is Kym plie scaped 1906 00:51:03,480 --> 00:51:03,490 high kinetic energy is Kym plie scaped 1907 00:51:03,490 --> 00:51:05,750 high kinetic energy is Kym plie scaped from the liquid went into the gas phase 1908 00:51:05,750 --> 00:51:05,760 from the liquid went into the gas phase 1909 00:51:05,760 --> 00:51:08,340 from the liquid went into the gas phase another molecule from the bulk will come 1910 00:51:08,340 --> 00:51:08,350 another molecule from the bulk will come 1911 00:51:08,350 --> 00:51:10,380 another molecule from the bulk will come and replace it so therefore at the 1912 00:51:10,380 --> 00:51:10,390 and replace it so therefore at the 1913 00:51:10,390 --> 00:51:12,420 and replace it so therefore at the surface as long as we have water at the 1914 00:51:12,420 --> 00:51:12,430 surface as long as we have water at the 1915 00:51:12,430 --> 00:51:15,000 surface as long as we have water at the surface the number of molecules which 1916 00:51:15,000 --> 00:51:15,010 surface the number of molecules which 1917 00:51:15,010 --> 00:51:17,970 surface the number of molecules which will be capable of escaping from the 1918 00:51:17,970 --> 00:51:17,980 will be capable of escaping from the 1919 00:51:17,980 --> 00:51:20,520 will be capable of escaping from the liquid to the gas will always be the 1920 00:51:20,520 --> 00:51:20,530 liquid to the gas will always be the 1921 00:51:20,530 --> 00:51:23,520 liquid to the gas will always be the same constant again that means that the 1922 00:51:23,520 --> 00:51:23,530 same constant again that means that the 1923 00:51:23,530 --> 00:51:25,020 same constant again that means that the number of molecules having kinetic 1924 00:51:25,020 --> 00:51:25,030 number of molecules having kinetic 1925 00:51:25,030 --> 00:51:26,880 number of molecules having kinetic energy let's assume that that kinetic 1926 00:51:26,880 --> 00:51:26,890 energy let's assume that that kinetic 1927 00:51:26,890 --> 00:51:27,750 energy let's assume that that kinetic energy you know 1928 00:51:27,750 --> 00:51:27,760 energy you know 1929 00:51:27,760 --> 00:51:29,580 energy you know minimum kinetic energy to escape from 1930 00:51:29,580 --> 00:51:29,590 minimum kinetic energy to escape from 1931 00:51:29,590 --> 00:51:31,410 minimum kinetic energy to escape from the liquid water to go into the gas is 1932 00:51:31,410 --> 00:51:31,420 the liquid water to go into the gas is 1933 00:51:31,420 --> 00:51:33,270 the liquid water to go into the gas is this amount right here so that means 1934 00:51:33,270 --> 00:51:33,280 this amount right here so that means 1935 00:51:33,280 --> 00:51:34,530 this amount right here so that means that at this temperature for example 1936 00:51:34,530 --> 00:51:34,540 that at this temperature for example 1937 00:51:34,540 --> 00:51:38,730 that at this temperature for example that many molecules at the surface is 1938 00:51:38,730 --> 00:51:38,740 that many molecules at the surface is 1939 00:51:38,740 --> 00:51:40,950 that many molecules at the surface is capable of escaping from the liquid 1940 00:51:40,950 --> 00:51:40,960 capable of escaping from the liquid 1941 00:51:40,960 --> 00:51:46,350 capable of escaping from the liquid right and it will be the same now what 1942 00:51:46,350 --> 00:51:46,360 right and it will be the same now what 1943 00:51:46,360 --> 00:51:48,720 right and it will be the same now what really happens as the time goes on at 1944 00:51:48,720 --> 00:51:48,730 really happens as the time goes on at 1945 00:51:48,730 --> 00:51:50,520 really happens as the time goes on at the beginning we have no gas what 1946 00:51:50,520 --> 00:51:50,530 the beginning we have no gas what 1947 00:51:50,530 --> 00:51:54,620 the beginning we have no gas what molecules then I will have simply 1948 00:51:54,620 --> 00:51:54,630 molecules then I will have simply 1949 00:51:54,630 --> 00:51:58,800 molecules then I will have simply molecules gases vapor whatever you call 1950 00:51:58,800 --> 00:51:58,810 molecules gases vapor whatever you call 1951 00:51:58,810 --> 00:52:01,680 molecules gases vapor whatever you call water molecules like this and going in 1952 00:52:01,680 --> 00:52:01,690 water molecules like this and going in 1953 00:52:01,690 --> 00:52:05,880 water molecules like this and going in this fashion but here is the point when 1954 00:52:05,880 --> 00:52:05,890 this fashion but here is the point when 1955 00:52:05,890 --> 00:52:07,950 this fashion but here is the point when you have all of these gas molecules 1956 00:52:07,950 --> 00:52:07,960 you have all of these gas molecules 1957 00:52:07,960 --> 00:52:10,560 you have all of these gas molecules which have kinetic energies higher than 1958 00:52:10,560 --> 00:52:10,570 which have kinetic energies higher than 1959 00:52:10,570 --> 00:52:13,890 which have kinetic energies higher than theirs for example either than that they 1960 00:52:13,890 --> 00:52:13,900 theirs for example either than that they 1961 00:52:13,900 --> 00:52:16,770 theirs for example either than that they will start colliding with each other now 1962 00:52:16,770 --> 00:52:16,780 will start colliding with each other now 1963 00:52:16,780 --> 00:52:18,480 will start colliding with each other now during the collisions there's going to 1964 00:52:18,480 --> 00:52:18,490 during the collisions there's going to 1965 00:52:18,490 --> 00:52:20,160 during the collisions there's going to be a kinetic energy transferred from one 1966 00:52:20,160 --> 00:52:20,170 be a kinetic energy transferred from one 1967 00:52:20,170 --> 00:52:22,140 be a kinetic energy transferred from one molecule to the other molecule so that 1968 00:52:22,140 --> 00:52:22,150 molecule to the other molecule so that 1969 00:52:22,150 --> 00:52:24,240 molecule to the other molecule so that simply means that if I look at the 1970 00:52:24,240 --> 00:52:24,250 simply means that if I look at the 1971 00:52:24,250 --> 00:52:26,490 simply means that if I look at the kinetic energy distribution in the gas 1972 00:52:26,490 --> 00:52:26,500 kinetic energy distribution in the gas 1973 00:52:26,500 --> 00:52:29,610 kinetic energy distribution in the gas phase molecules here it would also be 1974 00:52:29,610 --> 00:52:29,620 phase molecules here it would also be 1975 00:52:29,620 --> 00:52:34,680 phase molecules here it would also be something like this like that and that 1976 00:52:34,680 --> 00:52:34,690 something like this like that and that 1977 00:52:34,690 --> 00:52:37,050 something like this like that and that kinetic energy probably will corresponds 1978 00:52:37,050 --> 00:52:37,060 kinetic energy probably will corresponds 1979 00:52:37,060 --> 00:52:40,650 kinetic energy probably will corresponds to this point here this is let's say e 1980 00:52:40,650 --> 00:52:40,660 to this point here this is let's say e 1981 00:52:40,660 --> 00:52:42,840 to this point here this is let's say e kinetic energy of the molecules that 1982 00:52:42,840 --> 00:52:42,850 kinetic energy of the molecules that 1983 00:52:42,850 --> 00:52:45,540 kinetic energy of the molecules that they escaped from the gas from the 1984 00:52:45,540 --> 00:52:45,550 they escaped from the gas from the 1985 00:52:45,550 --> 00:52:47,610 they escaped from the gas from the liquid again into the gas like this so 1986 00:52:47,610 --> 00:52:47,620 liquid again into the gas like this so 1987 00:52:47,620 --> 00:52:49,530 liquid again into the gas like this so what does that means that means that 1988 00:52:49,530 --> 00:52:49,540 what does that means that means that 1989 00:52:49,540 --> 00:52:53,880 what does that means that means that there's going to be some molecules 1990 00:52:53,880 --> 00:52:53,890 there's going to be some molecules 1991 00:52:53,890 --> 00:52:56,640 there's going to be some molecules in the gas phase which have kinetic 1992 00:52:56,640 --> 00:52:56,650 in the gas phase which have kinetic 1993 00:52:56,650 --> 00:53:00,020 in the gas phase which have kinetic energy less than this amount over here 1994 00:53:00,020 --> 00:53:00,030 energy less than this amount over here 1995 00:53:00,030 --> 00:53:02,640 energy less than this amount over here now what does that means that means that 1996 00:53:02,640 --> 00:53:02,650 now what does that means that means that 1997 00:53:02,650 --> 00:53:05,370 now what does that means that means that when those molecules moving around here 1998 00:53:05,370 --> 00:53:05,380 when those molecules moving around here 1999 00:53:05,380 --> 00:53:08,550 when those molecules moving around here come and close to the surface they will 2000 00:53:08,550 --> 00:53:08,560 come and close to the surface they will 2001 00:53:08,560 --> 00:53:10,920 come and close to the surface they will be pulled into the liquid what does that 2002 00:53:10,920 --> 00:53:10,930 be pulled into the liquid what does that 2003 00:53:10,930 --> 00:53:14,520 be pulled into the liquid what does that means that means condensation right so 2004 00:53:14,520 --> 00:53:14,530 means that means condensation right so 2005 00:53:14,530 --> 00:53:17,910 means that means condensation right so now here I have evaporation and then I 2006 00:53:17,910 --> 00:53:17,920 now here I have evaporation and then I 2007 00:53:17,920 --> 00:53:20,370 now here I have evaporation and then I will have condensation as the time goes 2008 00:53:20,370 --> 00:53:20,380 will have condensation as the time goes 2009 00:53:20,380 --> 00:53:24,000 will have condensation as the time goes on now I can simply show that by a graph 2010 00:53:24,000 --> 00:53:24,010 on now I can simply show that by a graph 2011 00:53:24,010 --> 00:53:27,510 on now I can simply show that by a graph again as follow the rate again let's say 2012 00:53:27,510 --> 00:53:27,520 again as follow the rate again let's say 2013 00:53:27,520 --> 00:53:30,840 again as follow the rate again let's say this is the rate here increase in this 2014 00:53:30,840 --> 00:53:30,850 this is the rate here increase in this 2015 00:53:30,850 --> 00:53:33,480 this is the rate here increase in this fashion and let's say this is the time 2016 00:53:33,480 --> 00:53:33,490 fashion and let's say this is the time 2017 00:53:33,490 --> 00:53:39,500 fashion and let's say this is the time it goes on now the rate of evaporation 2018 00:53:39,500 --> 00:53:39,510 it goes on now the rate of evaporation 2019 00:53:39,510 --> 00:53:43,590 it goes on now the rate of evaporation will be constant again this is the rate 2020 00:53:43,590 --> 00:53:43,600 will be constant again this is the rate 2021 00:53:43,600 --> 00:53:48,570 will be constant again this is the rate of evaporation now what is the rate of 2022 00:53:48,570 --> 00:53:48,580 of evaporation now what is the rate of 2023 00:53:48,580 --> 00:53:50,370 of evaporation now what is the rate of the operation means that means the 2024 00:53:50,370 --> 00:53:50,380 the operation means that means the 2025 00:53:50,380 --> 00:53:53,130 the operation means that means the number of water molecules goes from 2026 00:53:53,130 --> 00:53:53,140 number of water molecules goes from 2027 00:53:53,140 --> 00:53:55,740 number of water molecules goes from liquid state to the gaseous state per 2028 00:53:55,740 --> 00:53:55,750 liquid state to the gaseous state per 2029 00:53:55,750 --> 00:53:59,160 liquid state to the gaseous state per second right that's what the rate is now 2030 00:53:59,160 --> 00:53:59,170 second right that's what the rate is now 2031 00:53:59,170 --> 00:54:01,680 second right that's what the rate is now since the number of molecules actually 2032 00:54:01,680 --> 00:54:01,690 since the number of molecules actually 2033 00:54:01,690 --> 00:54:03,990 since the number of molecules actually which at the surface considering the 2034 00:54:03,990 --> 00:54:04,000 which at the surface considering the 2035 00:54:04,000 --> 00:54:07,230 which at the surface considering the surface which is capable of escaping 2036 00:54:07,230 --> 00:54:07,240 surface which is capable of escaping 2037 00:54:07,240 --> 00:54:08,910 surface which is capable of escaping from liquid to the gas is always the 2038 00:54:08,910 --> 00:54:08,920 from liquid to the gas is always the 2039 00:54:08,920 --> 00:54:11,340 from liquid to the gas is always the same number that means that the rate 2040 00:54:11,340 --> 00:54:11,350 same number that means that the rate 2041 00:54:11,350 --> 00:54:14,070 same number that means that the rate will always be the same because the rate 2042 00:54:14,070 --> 00:54:14,080 will always be the same because the rate 2043 00:54:14,080 --> 00:54:16,380 will always be the same because the rate will be proportional to the number of 2044 00:54:16,380 --> 00:54:16,390 will be proportional to the number of 2045 00:54:16,390 --> 00:54:18,930 will be proportional to the number of molecules water molecules at the surface 2046 00:54:18,930 --> 00:54:18,940 molecules water molecules at the surface 2047 00:54:18,940 --> 00:54:21,030 molecules water molecules at the surface which have kinetic energy enough to 2048 00:54:21,030 --> 00:54:21,040 which have kinetic energy enough to 2049 00:54:21,040 --> 00:54:22,800 which have kinetic energy enough to escape from the liquid to the gas right 2050 00:54:22,800 --> 00:54:22,810 escape from the liquid to the gas right 2051 00:54:22,810 --> 00:54:25,740 escape from the liquid to the gas right so that will be constant now let's 2052 00:54:25,740 --> 00:54:25,750 so that will be constant now let's 2053 00:54:25,750 --> 00:54:30,150 so that will be constant now let's consider the condensation that means the 2054 00:54:30,150 --> 00:54:30,160 consider the condensation that means the 2055 00:54:30,160 --> 00:54:35,400 consider the condensation that means the reverse process in other words the 2056 00:54:35,400 --> 00:54:35,410 reverse process in other words the 2057 00:54:35,410 --> 00:54:38,520 reverse process in other words the molecules in a gas phase now due to 2058 00:54:38,520 --> 00:54:38,530 molecules in a gas phase now due to 2059 00:54:38,530 --> 00:54:42,320 molecules in a gas phase now due to their collisions think there's going to 2060 00:54:42,320 --> 00:54:42,330 their collisions think there's going to 2061 00:54:42,330 --> 00:54:45,630 their collisions think there's going to there's going to be kinetic energy 2062 00:54:45,630 --> 00:54:45,640 there's going to be kinetic energy 2063 00:54:45,640 --> 00:54:47,700 there's going to be kinetic energy distribution and some of the molecules 2064 00:54:47,700 --> 00:54:47,710 distribution and some of the molecules 2065 00:54:47,710 --> 00:54:49,560 distribution and some of the molecules in the gas phase will have low kinetic 2066 00:54:49,560 --> 00:54:49,570 in the gas phase will have low kinetic 2067 00:54:49,570 --> 00:54:51,210 in the gas phase will have low kinetic energy some will be a little higher and 2068 00:54:51,210 --> 00:54:51,220 energy some will be a little higher and 2069 00:54:51,220 --> 00:54:52,560 energy some will be a little higher and if the kinetic energy of the gas 2070 00:54:52,560 --> 00:54:52,570 if the kinetic energy of the gas 2071 00:54:52,570 --> 00:54:55,290 if the kinetic energy of the gas molecules lower than that value again it 2072 00:54:55,290 --> 00:54:55,300 molecules lower than that value again it 2073 00:54:55,300 --> 00:54:57,600 molecules lower than that value again it will go into the liquid phase pulled 2074 00:54:57,600 --> 00:54:57,610 will go into the liquid phase pulled 2075 00:54:57,610 --> 00:54:59,460 will go into the liquid phase pulled into the liquid phase so at the 2076 00:54:59,460 --> 00:54:59,470 into the liquid phase so at the 2077 00:54:59,470 --> 00:55:01,800 into the liquid phase so at the beginning that would be zero but as the 2078 00:55:01,800 --> 00:55:01,810 beginning that would be zero but as the 2079 00:55:01,810 --> 00:55:06,140 beginning that would be zero but as the time goes on then it will increase and 2080 00:55:06,140 --> 00:55:06,150 time goes on then it will increase and 2081 00:55:06,150 --> 00:55:13,390 time goes on then it will increase and let's call it rate of condensation I 2082 00:55:13,390 --> 00:55:13,400 2083 00:55:13,400 --> 00:55:17,359 guess there's a class here right okay 2084 00:55:17,359 --> 00:55:17,369 guess there's a class here right okay 2085 00:55:17,369 --> 00:55:19,519 guess there's a class here right okay now rate of condensation means what the 2086 00:55:19,519 --> 00:55:19,529 now rate of condensation means what the 2087 00:55:19,529 --> 00:55:21,410 now rate of condensation means what the number of molecules going from gas to 2088 00:55:21,410 --> 00:55:21,420 number of molecules going from gas to 2089 00:55:21,420 --> 00:55:24,559 number of molecules going from gas to the liquid per second after a certain 2090 00:55:24,559 --> 00:55:24,569 the liquid per second after a certain 2091 00:55:24,569 --> 00:55:27,019 the liquid per second after a certain time the rate of condensation becomes 2092 00:55:27,019 --> 00:55:27,029 time the rate of condensation becomes 2093 00:55:27,029 --> 00:55:30,680 time the rate of condensation becomes equal to the rate of evaporation what is 2094 00:55:30,680 --> 00:55:30,690 equal to the rate of evaporation what is 2095 00:55:30,690 --> 00:55:32,259 equal to the rate of evaporation what is that means we reach the equilibrium 2096 00:55:32,259 --> 00:55:32,269 that means we reach the equilibrium 2097 00:55:32,269 --> 00:55:34,849 that means we reach the equilibrium that's called dynamic equilibrium from 2098 00:55:34,849 --> 00:55:34,859 that's called dynamic equilibrium from 2099 00:55:34,859 --> 00:55:37,339 that's called dynamic equilibrium from that point on as long as the system is 2100 00:55:37,339 --> 00:55:37,349 that point on as long as the system is 2101 00:55:37,349 --> 00:55:39,680 that point on as long as the system is closed the temperature is the same there 2102 00:55:39,680 --> 00:55:39,690 closed the temperature is the same there 2103 00:55:39,690 --> 00:55:42,470 closed the temperature is the same there will be no change in the amount of 2104 00:55:42,470 --> 00:55:42,480 will be no change in the amount of 2105 00:55:42,480 --> 00:55:45,079 will be no change in the amount of liquids and no change in the amount of 2106 00:55:45,079 --> 00:55:45,089 liquids and no change in the amount of 2107 00:55:45,089 --> 00:55:47,720 liquids and no change in the amount of gas above it which is in equilibrium the 2108 00:55:47,720 --> 00:55:47,730 gas above it which is in equilibrium the 2109 00:55:47,730 --> 00:55:49,069 gas above it which is in equilibrium the process will continue 2110 00:55:49,069 --> 00:55:49,079 process will continue 2111 00:55:49,079 --> 00:55:50,509 process will continue that means evaporation and condensation 2112 00:55:50,509 --> 00:55:50,519 that means evaporation and condensation 2113 00:55:50,519 --> 00:55:53,269 that means evaporation and condensation will continue but the rate will be equal 2114 00:55:53,269 --> 00:55:53,279 will continue but the rate will be equal 2115 00:55:53,279 --> 00:55:55,609 will continue but the rate will be equal that means that the amount of liquid and 2116 00:55:55,609 --> 00:55:55,619 that means that the amount of liquid and 2117 00:55:55,619 --> 00:55:58,069 that means that the amount of liquid and amount of gas does not change and the 2118 00:55:58,069 --> 00:55:58,079 amount of gas does not change and the 2119 00:55:58,079 --> 00:56:01,489 amount of gas does not change and the pressure of the gas here after that 2120 00:56:01,489 --> 00:56:01,499 pressure of the gas here after that 2121 00:56:01,499 --> 00:56:04,190 pressure of the gas here after that equilibrium point actually at this point 2122 00:56:04,190 --> 00:56:04,200 equilibrium point actually at this point 2123 00:56:04,200 --> 00:56:08,059 equilibrium point actually at this point let's say t0 time is called the vapor 2124 00:56:08,059 --> 00:56:08,069 let's say t0 time is called the vapor 2125 00:56:08,069 --> 00:56:10,940 let's say t0 time is called the vapor pressure of that liquid at that 2126 00:56:10,940 --> 00:56:10,950 pressure of that liquid at that 2127 00:56:10,950 --> 00:56:15,380 pressure of that liquid at that temperature okay 2128 00:56:15,380 --> 00:56:15,390 temperature okay 2129 00:56:15,390 --> 00:56:18,769 temperature okay so let's continue this next time any 2130 00:56:18,769 --> 00:56:18,779 so let's continue this next time any 2131 00:56:18,779 --> 00:56:24,710 so let's continue this next time any questions okay