## delta G for Phase Changes

$\Delta G^{\circ}= \Delta H^{\circ} - T \Delta S^{\circ}$

$\Delta G^{\circ}= -RT\ln K$

$\Delta G^{\circ}= \sum \Delta G_{f}^{\circ}(products) - \sum \Delta G_{f}^{\circ}(reactants)$

Lily Guo 1D
Posts: 64
Joined: Fri Sep 29, 2017 7:03 am

### delta G for Phase Changes

Does delta G = 0 for phase changes at the proper melting/boiling points? For example, homework problem 9.91b says that the standard Gibbs free energy for the vaporization of water at 100°C is 0. Why is this? Does this apply for the fusion/vaporization of other substances at their melting/boiling points?

Rachel Lu_dis1H
Posts: 66
Joined: Fri Sep 29, 2017 7:06 am
Been upvoted: 1 time

### Re: delta G for Phase Changes

I believe that at phase changes, it is at equilibrium. And at equilibrium deltaG=0