What is the Gibbs free energy of the equation: Zr₂CN + 2O₂ (g) = ZrO₂ + ZrON + CO (g)?
a) ΔG = ΔH - TΔS
b) ΔG = ΔH + TΔS
c) ΔG = ΔH/T - ΔS
d) ΔG = ΔS - TΔH