Gibbs-Helmholtz equations

$H=-T^2{\frac{\partial (G/T)}{\partial T}|}_p$

$U=-T^2{\frac{\partial (A/T)}{\partial T}|}_V$

where

• $H$ is the enthalpy
• $T$ is the temperature
• $G$ is the Gibbs energy function
• $U$ is the internal energy,
• $V$ is the volume
• $A$ is the Helmholtz energy function.