---
title: "The particulate diagram below represents a mixture of \\(\\text{X}_2(g)\\), \\(\\text{Y}_2(g)\\), and \\(\\text{XY}(g)\\) in a rigid \\(1.0 \\text{ L}\\) container at a particular instant at \\(500 \\text{ K}\\).  \\[ \\text{X}_2(g) + \\text{Y}_2(g) \\rightleftharpoons 2\\,\\text{XY}(g) \\quad K_c = 4.0 \\text{ at } 500 \\text{ K} \\]  Based on the diagram, which of the following best explains whether the system is at equilibrium, and if not, in which direction the reaction will proceed to achieve equilibrium?"
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url: "https://nerd-notes.com/ubq/121525/"
date_modified: "2026-08-23T05:05:03+00:00"
---

# The particulate diagram below represents a mixture of \(\text{X}_2(g)\), \(\text{Y}_2(g)\), and \(\text{XY}(g)\) in a rigid \(1.0 \text{ L}\) container at a particular instant at \(500 \text{ K}\).

\[
\text{X}_2(g) + \text{Y}_2(g) \rightleftharpoons 2\,\text{XY}(g) \quad K_c = 4.0 \text{ at } 500 \text{ K}
\]

Based on the diagram, which of the following best explains whether the system is at equilibrium, and if not, in which direction the reaction will proceed to achieve equilibrium?

The particulate diagram below represents a mixture of \(\text{X}_2(g)\), \(\text{Y}_2(g)\), and \(\text{XY}(g)\) in a rigid \(1.0 \text{ L}\) container at a particular instant at \(500 \text{ K}\).

\[
\text{X}_2(g) + \text{Y}_2(g) \rightleftharpoons 2\,\text{XY}(g) \quad K_c = 4.0 \text{ at } 500 \text{ K}
\]

Based on the diagram, which of the following best explains whether the system is at equilibrium, and if not, in which direction the reaction will proceed to achieve equilibrium?

![A single rectangular box representing a sealed rigid vessel. A legend at the top right maps: open white circle = X atom, solid black circle = Y atom. Inside the container, there are exactly 10 diatomic molecules evenly distributed: exactly 4 homonuclear diatomic molecules consisting of two touching open white circles (representing X2), exactly 4 homonuclear diatomic molecules consisting of two touching solid black circles (representing Y2), and exactly 2 heteronuclear diatomic molecules each consisting of one open white circle touching one solid black circle (representing XY). Grayscale only. No individual particle is labeled. No other particles, labels, text, or annotations appear.](https://nerd-notes.com/wp-content/uploads/ubq-frq-generated/stem-fig-1-1787461502-KZ3nrv.jpg)

- **A.** The system is at equilibrium because \(Q_c = \dfrac{[\text{X}_2][\text{Y}_2]}{[\text{XY}]^2} = 4.0\), which equals \(K_c\).
- **B.** The system is not at equilibrium; the forward reaction will proceed to form more \(\text{XY}(g)\) because \(Q_c = 0.25 < K_c\).
- **C.** The system is not at equilibrium; the reverse reaction will proceed to form more \(\text{X}_2(g)\) and \(\text{Y}_2(g)\) because \(Q_c = 8.0 > K_c\).
- **D.** The system is at equilibrium because \(\text{X}_2(g)\), \(\text{Y}_2(g)\), and \(\text{XY}(g)\) are all present simultaneously in the container.

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/121525/*