1. The problem statement, all variables and given/known data What constraints are imposed on the use of the Gibbs equation Tds = dh - vdP 2. Relevant equations Tds = dh - vdP 3. The attempt at a solution I seem to be stuck on this question. So far I have come up with the following constraints, but I'm not even sure if they are correct: 1. The equation holds for only closed systems at constant pressure 2. The equations holds only for systems in which the free energy depends only on P and T. 3. The equation doesn't apply on mixtures or supercooled liquids.