oo. 



Dr. R. D. Kleeman on the 



and this is approximately equal to the heat of solution at 

 that temperature. If it is found that the heat of solution is 

 equal to this value, we may conclude that probably every 

 molecule 1 replaces a molecule 2 in the mixture. 



Let us apply these results to the heats of solution of a 

 number of gases in large quantities of water. The internal 

 heat of evaporation L 2 of a grm.-mol. of water into a vacuum 

 is given by 



<&<*« 



W-; 



)\ 



if the molecular weight of water is given by the chemical 

 formula H 2 0. But since the water molecules are polymerized 

 we must multiply M 2 and X\/ m 2 each by some appropriate 

 constant which expresses the degree of polymerization. The 

 formula may therefore be written 



w^tfTcs 



\2 



where u is a constant. The heat of evaporation L^ of a 

 grm.-mol. of molecules 1 from the solution is therefore 



L i=M 2 (jyf ) 2\/ m i 2\A's- 



From these two equations we have 



X \fm x 



L 1 = L 



Xs/\ 



where L t may now be taken as the heat of solution. 



The following table contains the heats of solution 

 per grm.-mol. of a number of gases in a large quantity 

 of water at a temperature of lb ,0 *2 C. They were taken 

 from Nernst's i Theoretical Chemistry/ 4th edit. p. 599. 



Gas. 



I 



Heat of Sol. 

 1 per grm.-mol. 



2 2Vw 2 



Gas. 



ci7.77. 



Heat of Sol. 

 per grm.-mol. 



■ 2v^. 



NH 3 . 



J 8,430 



11,370 



4,870 



20,060 



1 



HF... 



J 11,800 



9,033 



PIC1 ... 



17,310 



11,730 



HBr . 



J 19,940 



17,140 



co 2 ... 



5,880 



19,310 



HI.... 



J 19,210 



20,650 



1 









