Introduction

In thermodynamics, an important task is to develop relationships which express the nonmeasurable properties like U,H,A,G and S in terms of measurable properties P,V & T The number of partial derivatives of the type among the above eight properties are

If there exists a relation S=S (T,P) among the three variables S,T,P then

(32.1)

Dividing the above relation with dT while V is held constant, we obtain

(32.2)

There exists one relationship among four partial derivatives

(32.3)

Therefore a large number of relationships is possible among 336 partial derivatives.