302 



Mr. S. E. Milner on the Heats of 



Propyl Formate, HCOOC 3 H 7 . Mol. wt. 87«80. 



t. 



v. 



80 



1-199 



100 



1-238 



120 



1280 



140 



1-329 



160 



1-387 



180 



1-455 



200 



1-542 



220 



1-660 



240 



1-839 



325 



184 



111-5 

 70-4 

 459 

 30-9 

 21-2 

 14-5 

 9-6 



793 

 75-3 

 705 

 66-7 

 611 

 54-5 

 490 

 424 

 34-3 



b. 



a. 



0-898 



1-59 Xl0 9 



•899 



1-59 



•893 



1-56 



•899 



1-59 



•888 



1-56 



•860 



1-51 



•856 



1-52 



■849-1 - 



■860 r 



1-52 



1-58 



Ethyl Acetate 



, CH 3 COOC 2 H 6 . 



Mol. wt. < 



37-80. 



t. 



v. 



v'. 



u. 



b. 



a. 



80 



1-213 



285 



77-4 



0-903 



1-58 xlO 9 



100 



1-254 



162 



74-5 



•916 



1-63 



120 



1302 



970 



700 



•918 



1-63 



140 



1355 



606 



65-2 



•918 



1-63 



160 



1-422 



38-8 



58-4 



•900 



1-57 



180 



1-503 



25-75 



52-1 



•887 



1-55 



200 



1:610 



17-25 



45-5 



•886 



1 56 



220 



1-770 



11-23 



375 



•885 



1-57 



1 



It will be seen by inspection of the tables, that while the 

 value of b calculated from the heat of vaporization by equation 

 (9) as a rule diminishes fairly considerably with the tempera- 

 ture, that of a determined by its substitution in van der 

 Waals's equation remains approximately, and in some cases 

 very accurately constant. The experimental quantities in the 

 last tw^o or three cases seem somewhat less accurate than in 

 the others, and the numbers b obtained from them do not lie 

 at all well on a curve — and as a shows itself very sensitive 

 to the slightest changes in 5, its values here show somewhat 

 large divergences. Still an inspection of the numbers at low 

 and at high temperatures shows that the considerable 

 diminution in b that takes place is of such an amount as to 

 make the a determined from it approximately constant. The 

 slow fall to a minimum and subsequent rise of a in some cases 

 may be due either to some extent to experimental inaccuracy, 

 or more probably to equation (9) not holding completely 

 through a wide range of temperature, — as, indeed, with its 

 assumptions it can hardly be expected to do. . 



