The answer is 236.5 J/K
According to Δ G formula:
ΔG = ΔH - TΔS
when ΔG is the change in free energy (KJ)
and ΔH is the change in enthalpy (KJ)= ΔHvap * moles
= 71.8 KJ/mol * 1.11 mol
= 79.7 KJ
and T is the absolute temperature (K)= 64 °C + 273°C = 337 K
Δ S is the change in entropy KJ/K
by substitution:
when at equilibrium ΔG = 0
∴ΔS = ΔH / T
=79.7 KJ/ 337 K
= 0.2365 KJ/K
= 236.5 J/K
