Dissociation Coefficient with Temperature. 289 



^RT^log^^H+^S 



2n/K 2n/K \ 



} 



2n/K 2n/K 



VK + 40^ n/K ^K + 4C 2 + VK 

 The complete work of expansion W is w + w', or 



2ET 



{log 



^K+4C 1 -^/K n/K 



•K + 4C 2 - ^K VK + 4C 1 + n/K 



+ , VE ■ • • (7) 



This is the external work done by the osmotic pressure 

 while the solution expands isothermallj from concentration 

 Ql to C 2 , the equivalent W of heat being drawn from the 

 surroundings. A further amount of heat H is also absorbed 

 due to the dissociation of the dissolved substance as the dilu- 

 tion proceeds. The amount dissociated during the dilution is 



(& - !|)s r - mol8 - ; 



so that if Q is the heat absorbed in the dissociation of 1 gr. mol., 

 or 



-q^V / K + 4C 1 -\/k} . . (8) 



by (2) and (4). 



If this expansion against a semipermeable partition be 

 carried out at temperature T, and then the solution be brought 

 back to its original concentration Ci by a reverse process at a 

 temperature T — dT, the mechanical heat absorbed during this 



Phil. Mag. S. 5. Vol. 43. No. 263. April 1897. Z 



