364 

 and 



f,, I = ,.(;, or V,M.s^=»',fiG^ (7) 



By combination of (5) with (6) and (7) we then get: 



If we now express tiie internal e(|uilil)i'inm potentials of gaseous 

 .1 and e by; 



H'a^^ and ft'c^ 



then 



for internal equilibrium, so that instead of (8) we may also write: 

 2i (r/Os = I'jMGg — i',f«'ö^ + "if'c , — ï'.f^G , ... (9) 

 in which i'^Mö/. ^ '"sM'ü/j I'epresents the work done or gained when 

 we give the e((uilibriiim potential to r, mol. of gaseous B, which 

 possess the mol. potential of the saturate vapour, and thus 



»', ft'e 1 — I'l 1^0 ^ 

 represents the work performed or gained when r, mol. of gaseous 

 A are brought from the equilibrium potential on the potential of the 

 saturate vapour. 



These two values for the work are easy to compute. 

 We start from the equation : 



dn = — iidT -^ fdp (10) 



hence 



((/fi)y z= vdp (11) 



or 



((i)j,= I vdp = RTlnp -\- C 



from which follows that: 



li'G^ = RTlnp'A + C 



and l^G^^ RTlnp A + C 



or 



(i'g. - MG . = RTln ^— = RTln _!£.... (12) 

 ^ ^ PA Ca^ 



hence 



^\^^'G^—v,(iG^—v,RTln- (13) 



^G 



