Use the standard reaction enthalpies given below to determine Δ_rH° for the following reaction: 4SO₃(g) → 4S(s) + 6O₂(g) Δ_rH°= ?
Given:
SO₂(g) → S(s) + O₂(g) Δ_rH°= +296.8 kJ
2SO₂(g) + O₂(g) → 2SO₃(g) Δ_rH°= -197.8 kJ

Question

Quizplus · Accepted Answer

To find ΔrH° for 4SO3(g) → 4S(s) + 6O2(g), reverse the second reaction and multiply by 2: 4SO3(g) → 4SO2(g) + 2O2(g), ΔrH° = 2 * 197.8 kJ = 395.6 kJ. Then, multiply the first reaction by 4: 4SO2(g) → 4S(s) + 4O2(g), ΔrH° = 4 * 296.8 kJ = 1187.2 kJ. Add these: 395.6 kJ + 1187.2 kJ = 1582.8 kJ, which rounds to 1583 kJ.

Use the Standard Reaction Enthalpies Given Below to Determine ΔrH°

Use the Standard Reaction Enthalpies Given Below to Determine Δ_rH°