EQUATION AND THE NATURE OF COHESION. 49 



33. Propyl acetate. C' b H 1Q 2 . 



(a), a = 2.03 .BT c V e /l.0S — P C V 2 . T c = 549.2; P c = 25.227 

 mm.Hg.; d r = .2957; F", = 345.0 . . . a = 27.06 X I0 12 



(b). « = 6.5P r F, 2 a = 26.01 X I0 12 



(c). a = ixM 2 jM ( -l\ fi' = 93. 1 2 a = 30.45 X 10 12 



(d). a = C'ET r r r . 0' 5= 1.85.0 a = 29.16 X I0' 2 



(e). a = S3fJV l3 T r C/d . d = 1.179; 67=2.23 



(Morgan and Schwartz), if =102.. a = 26.93X10' 2 

 Here again the latent heat values are much higher than the 

 others and do not agree very well with each other. Omitting the 

 very high value of 30.45 the mean is 27.29 X 10 ' 2 ' The computa- 

 tion from the molecular weight and valences requires the same value 

 as for methyl butyrate, namely 26.96 X 10 12 which is only about 



1 °/o lower than the mean and almost exactly the value calculated 

 from the surface tension. Van Laar's value is 26.27 X 10 12 which 

 is not so far as usual from the truth. 



34. Ethyl propionate. C b H l() 2 . 



(a). a = 2.0S£T c F c /im — P c r c 2 . T r = 545.5; P,. = 25.217 

 mm.Hg. ; d e = . 2965 ; V c = 344.0 . . . a = 26.80 X 10' 2 



(b). a = 6.5 P C V 2 a = 25.86 X I0' 2 



(c). a = jti'J^/S dp. // = 91.59; J/=102.. a = 29.22X10 12 



(d). a = C'BT C V C . C' = 1.837 a = 28.69 X I0' 2 



[e). a = 3 MN^T r C/d v . d = 1.163; C = 2.23 

 (Morgan and Schwartz corrected accor- 

 ding to Lohnstein and Harkins). . . . a ==27.12 X 10 ' 2 

 The mean of these values is 27.54 X 10 12 . The value required by 

 the molecular weight and valences, is 26.96 X 10 12 . This is about 



2 °/o below the mean. 



35. Stannic chloride. SnCl A . 



(a), a = 2 . 03 BT C VJ\ . 03 — P,.V 2 . P r = 28.079 mm.Hg. ; 

 T c = 591.7; «?,. = . 741 9; r c =351'. a = 29.48X10 12 



(*). a =6.5 P C V 2 a = 30.07 X 10' 2 



{el a-= fj,'M 2 /Sd c 2 ' 3 . (i! = 26.51 ; J/=260.8 a =30.69 X 10 12 



(d). a = C'ÈT C V C . C' = 1.741 a = 30.12 X 10' 2 



. (e). a = SMN w T ( .C/d . C= 2.20 (Kistiarows- 



ky) ; d = 2.826 a = 30.50 X 10 l2 



The mean of these values is 30.17 X 10 12 . The value of a com- 

 puted from the molecular weight and number of valences, chlorine 



Verband, der Kon. Akad. v. Wetensch. (I e Sectie) Dl. XII N u . 4. D 4 



