[Big-Daddy]

Are the relationships between entropy change of the universe and Gibbs' free energy change analogous to the standard forms? i.e. are both of the following true?

ΔG°=ΔH°-T·ΔS_system°=-T·ΔS_universe°
ΔG=ΔH-T·ΔS_system=-T·ΔS_universe

So that ΔS_universe°>0 is a criterion for the equilibrium constant being greater than 1 whereas ΔS_universe>0 is a criterion for the forward reaction to spontaneously move forward?

[Big-Daddy]

I also have another connected question to add to this: surely simply saying "ΔH is temperature and pressure invariant" is not enough to say that ΔH=ΔH°, because if it was then the whole approach above would break down. In that case under what conditions does ΔH=ΔH°, and same for ΔS=ΔS°?