1. The problem statement, all variables and given/known data We have a Gibbs Free Energy function G=G(P, T, N1, N2) I am not writing the whole function because I just want a push in the right direction. Find expressions for the entropy, volume, internal energy, enthalpy and chemical potential. 2. Relevant equations Maxwell Relations T=(dU/dS) V and Ni constant -P=(dU/dV) S and Ni constant T=(dH/dS) P and Ni constant V=(dH/dP) S and Ni constant 3. The attempt at a solution I have found entropy, volume and chemical potential (partial molar gibbs free energy) functions using related equations. But I'm not sure on how to derive internal energy and enthalpy expressions. If I try to make use of above equations, for an example first equation dU=TdS so U=T.dS but also from second equation dU=-PdV so U=-PdV Can both be correct at the same time? I think they would yield different equations. If I am going absolutely wrong, do you have any idea on how to find U and H expressions. What other relations could be used?