Answer to Question #141583 in General Chemistry for Duke Cliffton

Question

You are given the following data.

S(s) + 3/2 O2(g) → SO3(g) ΔH = -395.2 kJ

2 SO2(g) + O2(g) → 2 SO3(g) ΔH = -198.2 kJ

Calculate ΔH for the reaction below.

S(s) + O2(g) → SO2(g)

Answer 1

S(s) + 3/2O₂(g) → SO₃(g) (I) ΔH₁ = -395.2 kJ

2SO₂(g) + O₂(g) → 2SO₃(g) (II) ΔH₂ = -198.2 kJ

(I) – 1/2(II)

S(s) + 3/2O₂(g) + SO₃ → SO₂(g) + 1/2O₂(g) + SO₃

S(s) + O₂(g) → SO₂(g)

ΔH = ΔH₁ – 1/2ΔH₂

ΔH = -395.2 +1/2(198.2) = -296.1 kJ