Gibbs energy of mixing for an athermic solution

Molar entropy and Gibbs energy of mixing for an athermic solution 

Using the general expression of the excess entropy [A.2.33], for the excess molar entropy of an athermic solution, we obtain  

As the molar enthalpy of mixing is null, the molar Gibbs energy of mixing is given by  

Molar heat capacity of an athermic solution The excess molar heat capacity is written simply as  

the molar heat capacity is the same as that for a perfect solution and therefore obeys Kopp s additivity law [A.2.14]. This law can be said to be fairly widely applicable, because we have seen it at woik with perfect solutions, regular solutions, athermic solutions and approximately with dilute ideal solutions. 

---