Theoretical Values of Solution Thermodynamic Functions

There have been several approaches to the expression of thermodynamic quantities of solutions. Scatchard published a series of papers (see 1801 and previous papers, especially 1802) based on the classical approach via chemical potentizil. Barker (130, 128, 131) applied the theory of conformal solutions (1254) to some H bonding systems after modifying it to allow for dipole attractions or, more generally, molecular orientations. The curves are similar in both cases. 

Scatchard s procedure is the basis for calculating excess thermodynamic functions (AH , A5 , AF )—the difference between the function for the ideal solution and actual solution of the same compo- 

It should be emphasized that the method is not limited to H bonding solutions. It is useful, for instance, in studying the thermodynamic consequences of mixing molecules of very different molecular size, as is done in polymer solutions. 

However, it is instructive to consider the results that are available for associated solutions in which AH is usually an order of magnitude larger than it is for non-H bonded systems. 

In general, we can say that A/i curves with a maximum result from breaking of H bonds, and the reverse is true for forming of H bonds. These generalities are hard to apply in those cases where Hbonds are both made and broken. 

---