Using Hess’s law, calculate Δ H for 2S(s) + 3O₂(g) → 2SO₃(g) given: S(s) + O₂(g) → SO₂(g), Δ H = -296.8 kJ/mol; 2SO₂(g)

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Using Hess’s law, calculate Δ H for 2S(s) + 3O₂(g) → 2SO₃(g) given: S(s) + O₂(g) → SO₂(g), Δ H = -296.8 kJ/mol; 2SO₂(g) + O₂(g) → 2SO₃(g), Δ H = -197.8 kJ/mol.

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-494.6 kJ 791.4 kJ -791.4 kJ Correct -98.9 kJ

Multiply first by 2: 2S(s) + 2O₂(g) → 2SO₂(g), Δ H = -593.6 kJ. Add second: Δ H = -593.6 + (-197.8) = -791.4 kJ.

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