1. Using the following reactions, calculate the heat of formation, 4Hf, of

H₂S using Hess' Law. SHOW ALL YOUR WORK.

(1) H₂(g) + 1/2O₂(g) → H₂O(l) + 285.8 kJ

(2) 2H₂S(g) + 30₂(g) →2SO₂(g) + 2H₂O(l) + 1124.0 kJ

(3) S(s) + O₂(g) → SO₂(g) + 296.8 kJ