---
title: "A reaction system at \\(298 \\text{ K}\\) is represented by the balanced equation below.  \\(\\text{2 NO}_2\\text{(g)} \\rightleftharpoons \\text{N}_2\\text{O}_4\\text{(g)} \\quad K_c = 2.0 \\text{ at } 298 \\text{ K}\\)  A student prepares a mixture of \\(\\text{NO}_2\\text{(g)}\\) and \\(\\text{N}_2\\text{O}_4\\text{(g)}\\) in a rigid \\(1.0 \\text{ L}\\) container at \\(298 \\text{ K}\\), as represented in the particulate diagram. Each molecule in the diagram represents \\(1.0 \\text{ mol}\\) of that species. Which of the following best predicts how the system will respond to reach equilibrium?"
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url: "https://nerd-notes.com/ubq/119419/"
date_modified: "2026-08-19T12:40:14+00:00"
---

# A reaction system at \(298 \text{ K}\) is represented by the balanced equation below.

\(\text{2 NO}_2\text{(g)} \rightleftharpoons \text{N}_2\text{O}_4\text{(g)} \quad K_c = 2.0 \text{ at } 298 \text{ K}\)

A student prepares a mixture of \(\text{NO}_2\text{(g)}\) and \(\text{N}_2\text{O}_4\text{(g)}\) in a rigid \(1.0 \text{ L}\) container at \(298 \text{ K}\), as represented in the particulate diagram. Each molecule in the diagram represents \(1.0 \text{ mol}\) of that species. Which of the following best predicts how the system will respond to reach equilibrium?

A reaction system at \(298 \text{ K}\) is represented by the balanced equation below.

\(\text{2 NO}_2\text{(g)} \rightleftharpoons \text{N}_2\text{O}_4\text{(g)} \quad K_c = 2.0 \text{ at } 298 \text{ K}\)

A student prepares a mixture of \(\text{NO}_2\text{(g)}\) and \(\text{N}_2\text{O}_4\text{(g)}\) in a rigid \(1.0 \text{ L}\) container at \(298 \text{ K}\), as represented in the particulate diagram. Each molecule in the diagram represents \(1.0 \text{ mol}\) of that species. Which of the following best predicts how the system will respond to reach equilibrium?

![A schematic diagram shows a rigid 1.0 L container containing a mixture of gases with a legend at the top right. The legend maps: a single dark-gray circle attached to two light-gray circles represents an NO2 molecule; two bonded dark-gray circles, each attached to two light-gray circles, represents an N2O4 molecule. Inside the container, there are exactly 2 NO2 molecules and exactly 6 N2O4 molecules randomly distributed throughout the volume. No other particles, labels, text, or annotations appear.](https://nerd-notes.com/wp-content/uploads/ubq-frq-generated/stem-fig-1-1787143214-Lgut9D.jpg)

- **A.** The system is already at equilibrium because both \(\text{NO}_2\text{(g)}\) and \(\text{N}_2\text{O}_4\text{(g)}\) are present in the vessel.
- **B.** The reaction will shift to the left to form more \(\text{NO}_2\text{(g)}\) because \(Q_c > K_c\).
- **C.** The reaction will shift to the right to form more \(\text{N}_2\text{O}_4\text{(g)}\) because \(Q_c < K_c\).
- **D.** The reaction will shift to the left to form more \(\text{NO}_2\text{(g)}\) because the number of product molecules exceeds the number of reactant molecules.

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/119419/*