For the reaction CuS(s) + H
2(g)
H
2S(g) + Cu(s),
ΔG°
f (CuS) = –53.6 kJ/mol
ΔG°
f (H
2S) = –33.6 kJ/mol
ΔH°
f (CuS) = –53.1 kJ/mol
ΔH°
f (H
2S) = –20.6 kJ/mol
Calculate ΔG at 798 K and 1 atm pressure (assume ΔS°
and ΔH° do not change with temperature).