Chemistry unit 6

A reversible isomerisation U to V has ΔH = +12 kJ mol-1 and ΔS = +40 J mol-1 K-1, treated as constant between 250 and 400 K. Standard free energy is ΔG° = ΔH-TΔS. Equilibrium obeys ΔG° = -RT ln K, with K=[V]/[U] and R positive. A catalyst changes activation barriers but not the energies of U and V. The closed system contains only these two isomers.