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title: "Consider the gas-phase decomposition reaction represented below, for which \\(\\Delta G^\\circ = +4.8\\text{ kJ/mol}_{rxn}\\) and \\(K_p = 0.14\\) at \\(298\\text{ K}\\).  \\[\\text{N}_2\\text{O}_4(g) \\rightleftharpoons 2\\,\\text{NO}_2(g)\\]  A rigid, evacuated container at \\(298\\text{ K}\\) is charged with \\(\\text{N}_2\\text{O}_4(g)\\) at an initial partial pressure of \\(2.0\\text{ atm}\\) and \\(\\text{NO}_2(g)\\) at an initial partial pressure of \\(0.10\\text{ atm}\\). Which of the following correctly predicts the initial direction in which the reaction will proceed to establish equilibrium, along with the appropriate thermodynamic justification?"
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url: "https://nerd-notes.com/ubq/123920/"
date_modified: "2026-09-28T12:32:12+00:00"
---

# Consider the gas-phase decomposition reaction represented below, for which \(\Delta G^\circ = +4.8\text{ kJ/mol}_{rxn}\) and \(K_p = 0.14\) at \(298\text{ K}\).

\[\text{N}_2\text{O}_4(g) \rightleftharpoons 2\,\text{NO}_2(g)\]

A rigid, evacuated container at \(298\text{ K}\) is charged with \(\text{N}_2\text{O}_4(g)\) at an initial partial pressure of \(2.0\text{ atm}\) and \(\text{NO}_2(g)\) at an initial partial pressure of \(0.10\text{ atm}\). Which of the following correctly predicts the initial direction in which the reaction will proceed to establish equilibrium, along with the appropriate thermodynamic justification?

Consider the gas-phase decomposition reaction represented below, for which \(\Delta G^\circ = +4.8\text{ kJ/mol}_{rxn}\) and \(K_p = 0.14\) at \(298\text{ K}\).

\[\text{N}_2\text{O}_4(g) \rightleftharpoons 2\,\text{NO}_2(g)\]

A rigid, evacuated container at \(298\text{ K}\) is charged with \(\text{N}_2\text{O}_4(g)\) at an initial partial pressure of \(2.0\text{ atm}\) and \(\text{NO}_2(g)\) at an initial partial pressure of \(0.10\text{ atm}\). Which of the following correctly predicts the initial direction in which the reaction will proceed to establish equilibrium, along with the appropriate thermodynamic justification?

- **A.** The reaction will proceed in the reverse direction because \(\Delta G^\circ > 0\), which indicates that the forward reaction is nonspontaneous under all pressure conditions.
- **B.** The reaction will proceed in the reverse direction because \(Q_p > K_p\), which makes the instantaneous free energy change, \(\Delta G\), positive for the forward process.
- **C.** The reaction will proceed in the forward direction because \(\Delta G^\circ\) decreases and becomes negative as \(\text{N}_2\text{O}_4(g)\) is consumed.
- **D.** The reaction will proceed in the forward direction because \(Q_p < K_p\), which results in an instantaneous free energy change of \(\Delta G < 0\) despite \(\Delta G^\circ\) being positive.

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/123920/*