Introduction
Many thermodynamic equations are expressed in terms of partial derivatives. For example, the expression for the heat capacity at constant pressure is:
which is the partial derivative of the enthalpy with respect to temperature while holding pressure constant. We may write this equation as:
This method of rewriting the partial derivative was described by Bridgman (and also Lewis & Randall), and allows the use of the following collection of expressions to express many thermodynamic equations. For example from the equations below we have:
and
Dividing, we recover the proper expression for CP.
The following summary restates various partial terms in terms of the thermodyamic potentials, the state parameters S, T, P, V, and the following three material properties which are easily measured experimentally.
Read more about this topic: Bridgman's Thermodynamic Equations
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