Intermediate Thermodynamics Thermodynamic Properties

Abstract

Fundamentals: Important property relations start from the first and second Tds equations: du dv P ds T = − (1) dh dP v ds T = + (2) We define now two additional properties, the Helmholtz function a and the Gibbs function g: s T u a − ≡ (3) s T h g − ≡ (4) Taking differentials in Eqs. (3) and (4) and using expressions (1) and (2) we can write: dT s dv P da − − = (5) dT s dP v dg − = (6) Eqs. (1), (2), (5) and (6) are called gibbsian equations. If we apply the test for exactness to these equations we obtain the Maxwell relations: v s s P v