Gibbs free energy

Gibbs free energy, for all phases, is calculated from:

G = H - T S

for which enthalpy and entropy need to be available.

For the overall phase, Gibbs free energy can be calculated by summation over the existing phases, taking phase fraction into account.

If TEA's internal calculation routines for enthalpy and entropy are used, the Gibbs energy will not include the formation terms (heat of formation and entropy of formation).