Question

What is `DeltaG` for a solid melting at its normal melting point?

Answer 1

`DeltaG` is `0` for a process at constant `T` and `P`.

Since we are looking at the normal melting point of water ice, it means that we are at a constant `T_"nmp"` and `P_"norm" = "1 atm"`.

From the Maxwell Relation:

`dG = -SdT + VdP`

But at constant `T` and `P`, `dT = 0` and `dP = 0`. Therefore:

`color(blue)(DeltaG_"melt") = -S(0) + V(0) = color(blue)(0)`