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title: "A mixture of \\(\\text{SO}_2(g)\\), \\(\\text{O}_2(g)\\), and \\(\\text{SO}_3(g)\\) is held at equilibrium inside a cylinder fitted with a movable piston at a constant temperature according to the following equation: \\[ 2\\,\\text{SO}_2(g) + \\text{O}_2(g) \\rightleftharpoons 2\\,\\text{SO}_3(g) \\qquad \\Delta H^\\circ = -198\\text{ kJ/mol}_{\\text{rxn}} \\] The volume of the container is suddenly halved at constant temperature. Which of the following correctly predicts the direction the reaction shifts to re-establish equilibrium, along with the correct justification comparing \\(Q_c\\) and \\(K_c\\) immediately following the volume change?"
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url: "https://nerd-notes.com/ubq/121395/"
date_modified: "2026-08-23T05:02:04+00:00"
---

# A mixture of \(\text{SO}_2(g)\), \(\text{O}_2(g)\), and \(\text{SO}_3(g)\) is held at equilibrium inside a cylinder fitted with a movable piston at a constant temperature according to the following equation: \[ 2\,\text{SO}_2(g) + \text{O}_2(g) \rightleftharpoons 2\,\text{SO}_3(g) \qquad \Delta H^\circ = -198\text{ kJ/mol}_{\text{rxn}} \] The volume of the container is suddenly halved at constant temperature. Which of the following correctly predicts the direction the reaction shifts to re-establish equilibrium, along with the correct justification comparing \(Q_c\) and \(K_c\) immediately following the volume change?

A mixture of \(\text{SO}_2(g)\), \(\text{O}_2(g)\), and \(\text{SO}_3(g)\) is held at equilibrium inside a cylinder fitted with a movable piston at a constant temperature according to the following equation: \[ 2\,\text{SO}_2(g) + \text{O}_2(g) \rightleftharpoons 2\,\text{SO}_3(g) \qquad \Delta H^\circ = -198\text{ kJ/mol}_{\text{rxn}} \] The volume of the container is suddenly halved at constant temperature. Which of the following correctly predicts the direction the reaction shifts to re-establish equilibrium, along with the correct justification comparing \(Q_c\) and \(K_c\) immediately following the volume change?

- **A.** The system shifts to the left because \(Q_c > K_c\).
- **B.** The system shifts to the left because \(Q_c < K_c\).
- **C.** The system shifts to the right because \(Q_c < K_c\).
- **D.** The system shifts to the right because \(Q_c > K_c\).

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/121395/*