52:
95:
or the gas phase has a lower chemical potential and is more energetically favorable than the other phase. This means that when a nonvolatile solute is added, the chemical potential of the solvent in the liquid phase is decreased by dilution, but the chemical potential of the solvent in the gas phase is not affected. This means in turn that the equilibrium between the liquid and gas phase is established at another temperature for a solution than a pure liquid, i.e., the boiling point is elevated.
67:, which means that it is dependent on the presence of dissolved particles and their number, but not their identity. It is an effect of the dilution of the solvent in the presence of a solute. It is a phenomenon that happens for all solutes in all solutions, even in ideal solutions, and does not depend on any specific soluteâsolvent interactions. The boiling point elevation happens both when the solute is an
94:
Put in chemical potential terms, at the boiling point, the liquid phase and the gas (or vapor) phase have the same chemical potential (or vapor pressure) meaning that they are energetically equivalent. The chemical potential is dependent on the temperature, and at other temperatures either the liquid
370:
of the solution. If the solute is also volatile, one of the key assumptions used in deriving the formula is not true, since it derived for solutions of non-volatile solutes in a volatile solvent. In the case of volatile solutes it is more relevant to talk of a mixture of volatile compounds and the
90:
Put in vapor pressure terms, a liquid boils at the temperature when its vapor pressure equals the surrounding pressure. For the solvent, the presence of the solute decreases its vapor pressure by dilution. A nonvolatile solute has a vapor pressure of zero, so the vapor pressure of the solution is
102:
is analogous to boiling point elevation. However, the magnitude of the freezing point depression is larger than the boiling point elevation for the same solvent and the same concentration of a solute. Because of these two phenomena, the liquid range of a solvent is increased in the presence of a
550:. Furthermore, the cryoscopic constant that determines freezing-point depression is larger than the ebullioscopic constant, and since the freezing point is often easier to measure with precision, it is more common to use
38:
has a higher boiling point than a pure solvent. This happens whenever a non-volatile solute, such as a salt, is added to a pure solvent, such as water. The boiling point can be measured accurately using an
87:
of the solvent. In both cases, the explanation depends on the fact that many solutes are only present in the liquid phase and do not enter into the gas phase (except at extremely high temperatures).
119:
together with the assumption of the non-volatility of the solute. The result is that in dilute ideal solutions, the extent of boiling-point elevation is directly proportional to the
375:
of the mixture. In such cases, the mixture can sometimes have a boiling point that is lower than either of the pure components; a mixture with a minimum boiling point is a type of
91:
less than the vapor pressure of the solvent. Thus, a higher temperature is needed for the vapor pressure to reach the surrounding pressure, and the boiling point is elevated.
252:
into account since the boiling point elevation is a colligative property, dependent on the number of particles in solution. This is most easily done by using the
967:
578:
669:
55:
The change in chemical potential of a solvent when a solute is added explains why boiling point elevation takes place.
714:
611:
662:
112:
804:
515:
Together with the formula above, the boiling-point elevation can in principle be used to measure the degree of
285:
accounts for the number of individual particles (typically ions) formed by a compound in solution. Examples:
1033:
1028:
957:
329:
factors result from ion pairs in solution, which lower the effective number of particles in the solution.
1038:
887:
655:
51:
942:
834:
568:
99:
819:
754:
516:
249:
774:
872:
867:
724:
563:
245:
178:
972:
952:
253:
367:
686:
678:
547:
546:
measurements are difficult to carry out, which was partly overcome by the invention of the
457:
232:
64:
35:
624:
573:
305:
in water, due to the near full dissociation of NaCl into Na and Cl (often simplified as 2)
8:
799:
769:
84:
977:
936:
839:
607:
912:
907:
739:
699:
444:
312:
897:
882:
814:
779:
764:
759:
744:
709:
302:
116:
947:
902:
892:
809:
704:
694:
181:, which is dependent on the properties of the solvent. It can be calculated as
80:
72:
1022:
992:
829:
789:
734:
532:
372:
23:
849:
844:
536:
210:
40:
1002:
917:
470:
418:
68:
106:
997:
987:
982:
859:
520:
371:
effect of the solute on the boiling point must be determined from the
1007:
962:
877:
647:
551:
376:
111:
The extent of boiling-point elevation can be calculated by applying
824:
120:
927:
729:
719:
431:
366:
At high concentrations, the above formula is less precise due to
292:
76:
31:
34:) will be higher when another compound is added, meaning that a
483:
27:
749:
528:
496:
16:
Elevation of boiling point due to addition of a compound
107:
The equation for calculations at dilute concentration
968:
List of boiling and freezing information of solvents
579:
List of boiling and freezing information of solvents
75:
terms, the origin of the boiling point elevation is
606:, 4th Ed., Oxford University Press, Oxford, 1994,
523:of the solute. This kind of measurement is called
121:molal concentration (amount of substance per mass)
71:, such as various salts, and a nonelectrolyte. In
315:in water, due to nearly full dissociation of CaCl
220:is the boiling temperature of the pure solvent ,
153:where the boiling point elevation, is defined as
1020:
625:"Colligative Properties and Molality - UBC Wiki"
332:Equation after including the van 't Hoff factor
663:
281:is the molality of the solution. The factor
123:of the solution according to the equation:
670:
656:
382:
598:
596:
594:
50:
319:into Ca and 2Cl (often simplified as 3)
1021:
677:
387:Values of the ebullioscopic constants
224:is the molar mass of the solvent, and
651:
591:
79:and can be explained in terms of the
535:"boiling-viewing"). However, since
13:
14:
1050:
539:is difficult to avoid, precise
631:
617:
46:
22:is the phenomenon whereby the
1:
641:, 4th Ed., p. C17 (Table 7.2)
584:
958:Inorganic nonaqueous solvent
7:
557:
113:ClausiusâClapeyron relation
10:
1055:
943:Acid dissociation constant
926:
858:
788:
685:
569:Freezing point depression
100:freezing-point depression
406:Ebullioscopic constant
235:per mole of the solvent.
908:Solubility table (data)
775:Apparent molar property
510:
394:for selected solvents:
383:Ebullioscopic constants
248:, calculated by taking
61:boiling point elevation
20:Boiling-point elevation
873:Total dissolved solids
868:Solubility equilibrium
793:and related quantities
564:Colligative properties
179:ebullioscopic constant
56:
973:Partition coefficient
953:Polar aprotic solvent
54:
888:Enthalpy of solution
815:Volume concentration
810:Number concentration
548:Beckmann thermometer
458:Carbon tetrachloride
246:colligative molality
233:heat of vaporization
65:colligative property
1034:Chemical properties
1029:Amount of substance
800:Molar concentration
770:Dilution (equation)
403:Boiling point in °C
1039:Physical chemistry
840:Isotopic abundance
805:Mass concentration
679:Chemical solutions
639:Physical Chemistry
604:Physical Chemistry
254:van 't Hoff factor
98:The phenomenon of
85:chemical potential
57:
1016:
1015:
508:
507:
413:in units of or
1046:
913:Solubility chart
740:Phase separation
700:Aqueous solution
672:
665:
658:
649:
648:
642:
635:
629:
628:
621:
615:
600:
445:Carbon disulfide
397:
396:
313:calcium chloride
165:b (pure solvent)
1054:
1053:
1049:
1048:
1047:
1045:
1044:
1043:
1019:
1018:
1017:
1012:
922:
883:Solvation shell
854:
792:
784:
780:Miscibility gap
765:Serial dilution
760:Supersaturation
710:Buffer solution
681:
676:
646:
645:
636:
632:
623:
622:
618:
601:
592:
587:
560:
545:
513:
412:
393:
385:
362:
357:
350:
343:
318:
303:sodium chloride
280:
272:
265:
243:
230:
219:
204:
194:
187:
176:
166:
159:
149:
148:
141:
134:
109:
49:
17:
12:
11:
5:
1052:
1042:
1041:
1036:
1031:
1014:
1013:
1011:
1010:
1005:
1000:
995:
990:
985:
980:
975:
970:
965:
960:
955:
950:
948:Protic solvent
945:
940:
932:
930:
924:
923:
921:
920:
915:
910:
905:
900:
895:
893:Lattice energy
890:
885:
880:
875:
870:
864:
862:
856:
855:
853:
852:
847:
842:
837:
832:
827:
822:
817:
812:
807:
802:
796:
794:
786:
785:
783:
782:
777:
772:
767:
762:
757:
752:
747:
745:Eutectic point
742:
737:
732:
727:
722:
717:
712:
707:
705:Solid solution
702:
697:
695:Ideal solution
691:
689:
683:
682:
675:
674:
667:
660:
652:
644:
643:
637:P. W. Atkins,
630:
616:
602:P. W. Atkins,
589:
588:
586:
583:
582:
581:
576:
574:DĂźhring's rule
571:
566:
559:
556:
543:
512:
509:
506:
505:
502:
499:
493:
492:
489:
486:
480:
479:
476:
473:
467:
466:
463:
460:
454:
453:
450:
447:
441:
440:
437:
434:
428:
427:
424:
421:
415:
414:
410:
404:
401:
391:
384:
381:
364:
363:
355:
348:
341:
336:
323:
322:
321:
320:
316:
306:
296:
278:
270:
263:
241:
236:
228:
217:
202:
192:
185:
174:
164:
157:
151:
150:
146:
139:
132:
127:
108:
105:
81:vapor pressure
48:
45:
15:
9:
6:
4:
3:
2:
1051:
1040:
1037:
1035:
1032:
1030:
1027:
1026:
1024:
1009:
1006:
1004:
1001:
999:
996:
994:
991:
989:
986:
984:
981:
979:
976:
974:
971:
969:
966:
964:
961:
959:
956:
954:
951:
949:
946:
944:
941:
938:
934:
933:
931:
929:
925:
919:
916:
914:
911:
909:
906:
904:
901:
899:
896:
894:
891:
889:
886:
884:
881:
879:
876:
874:
871:
869:
866:
865:
863:
861:
857:
851:
848:
846:
843:
841:
838:
836:
835:Mass fraction
833:
831:
830:Mole fraction
828:
826:
823:
821:
818:
816:
813:
811:
808:
806:
803:
801:
798:
797:
795:
791:
790:Concentration
787:
781:
778:
776:
773:
771:
768:
766:
763:
761:
758:
756:
753:
751:
748:
746:
743:
741:
738:
736:
735:Phase diagram
733:
731:
728:
726:
723:
721:
718:
716:
715:FloryâHuggins
713:
711:
708:
706:
703:
701:
698:
696:
693:
692:
690:
688:
684:
680:
673:
668:
666:
661:
659:
654:
653:
650:
640:
634:
626:
620:
613:
612:0-19-269042-6
609:
605:
599:
597:
595:
590:
580:
577:
575:
572:
570:
567:
565:
562:
561:
555:
553:
549:
542:
538:
534:
530:
526:
522:
518:
503:
500:
498:
495:
494:
490:
487:
485:
482:
481:
477:
474:
472:
469:
468:
464:
461:
459:
456:
455:
451:
448:
446:
443:
442:
438:
435:
433:
430:
429:
425:
422:
420:
417:
416:
409:
405:
402:
399:
398:
395:
390:
380:
378:
374:
373:phase diagram
369:
361:
354:
347:
340:
335:
334:
333:
330:
328:
314:
310:
307:
304:
300:
297:
294:
290:
287:
286:
284:
276:
269:
262:
258:
255:
251:
247:
240:
237:
234:
227:
223:
216:
212:
208:
201:
197:
191:
184:
180:
173:
170:
169:
168:
163:
156:
145:
138:
131:
126:
125:
124:
122:
118:
114:
104:
101:
96:
92:
88:
86:
82:
78:
74:
73:thermodynamic
70:
66:
62:
53:
44:
42:
37:
33:
29:
25:
24:boiling point
21:
898:Raoult's law
850:Ternary plot
845:Mixing ratio
638:
633:
619:
614:, p. 222-225
603:
540:
537:superheating
525:ebullioscopy
524:
517:dissociation
514:
407:
388:
386:
365:
359:
352:
345:
338:
331:
326:
325:Non integer
324:
308:
298:
288:
282:
274:
267:
260:
256:
250:dissociation
238:
225:
221:
214:
211:gas constant
206:
199:
195:
189:
182:
171:
161:
158:b (solution)
154:
152:
143:
136:
129:
117:Raoult's law
110:
97:
93:
89:
60:
58:
41:ebullioscope
19:
18:
1003:Lyonium ion
918:Miscibility
903:Henry's law
471:Naphthalene
419:Acetic acid
368:nonideality
69:electrolyte
47:Explanation
1023:Categories
998:Amphiphile
993:Lipophilic
988:Hydrophile
983:Hydrophobe
860:Solubility
755:Saturation
725:Suspension
585:References
521:molar mass
311:= 2.3 for
301:= 1.9 for
1008:Lyate ion
963:Solvation
878:Solvation
820:Normality
552:cryoscopy
377:azeotrope
277:, where b
978:Polarity
937:Category
825:Molality
687:Solution
558:See also
400:Compound
295:in water
291:= 1 for
205:, where
103:solute.
77:entropic
36:solution
928:Solvent
730:Colloid
720:Mixture
519:or the
432:Benzene
244:is the
231:is the
209:is the
32:solvent
610:
504:0.512
488:181.75
484:Phenol
356:solute
279:solute
271:solute
213:, and
177:, the
28:liquid
750:Alloy
533:Greek
529:Latin
497:Water
491:3.04
475:217.9
465:4.95
452:2.37
439:2.53
426:3.07
423:118.1
293:sugar
63:is a
26:of a
608:ISBN
511:Uses
478:5.8
462:76.8
449:46.2
436:80.1
115:and
59:The
501:100
259:as
83:or
30:(a
1025::
593:^
554:.
541:ÎT
379:.
358:¡
351:¡
344:=
273:¡
266:=
226:ÎH
200:ÎH
190:RT
188:=
167:.
160:â
142:¡
135:=
43:.
939:)
935:(
671:e
664:t
657:v
627:.
544:b
531:-
527:(
411:b
408:K
392:b
389:K
360:i
353:b
349:b
346:K
342:b
339:T
337:Î
327:i
317:2
309:i
299:i
289:i
283:i
275:i
268:b
264:c
261:b
257:i
242:c
239:b
229:v
222:M
218:b
215:T
207:R
203:v
198:/
196:M
193:b
186:b
183:K
175:b
172:K
162:T
155:T
147:c
144:b
140:b
137:K
133:b
130:T
128:Î
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