H 2 S(g) + 2 O 2 (g) SO 3 (g) + H 2 O(l) H 2 S(g) + 2 O 2 (g) H 2 SO 4 (l) ΔH = - 392.5 kJ H 2 SO 4 (l) SO 3 (g) + H 2 O(g) ΔH = +102.5 kJ H 2 O(g)
