Gibbs-Helmholtz equation
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The Gibbs-Helmholtz equation is a thermodynamic relationship useful for calculating changes in the energy or enthalpy (heat content) of a system. Two useful general forms of this equation are:
- <math>\Delta A - \Delta U = T \left( \frac{\delta\left(\Delta A \right)}{\delta T} \right)_V<math>
- <math>\Delta G - \Delta H = T \left( \frac{\delta \left( \Delta G\right)}{\delta T} \right)_P<math>
Where A is the work function, U is the internal energy of the system, T is the absolute temperature, V is the volume, P is the pressure, G is the Gibbs free energy and H is the heat content(enthalpy) of the system.