---
title: "A student investigates the heterogeneous gas-phase equilibrium shown below at a constant temperature \\(T\\). \\[ \\text{C}(s) + \\text{H}_2\\text{O}(g) \\rightleftharpoons \\text{CO}(g) + \\text{H}_2(g) \\] The particulate diagram below represents an equilibrium mixture of the system in a rigid container of volume \\(V\\).  The volume of the container is increased to \\(3V\\) at constant temperature \\(T\\), and the system is allowed to reach equilibrium. Which of the following particulate diagrams best represents the system after equilibrium is re-established in the larger volume?"
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url: "https://nerd-notes.com/ubq/123902/"
date_modified: "2026-09-28T12:31:00+00:00"
---

# A student investigates the heterogeneous gas-phase equilibrium shown below at a constant temperature \(T\).
\[ \text{C}(s) + \text{H}_2\text{O}(g) \rightleftharpoons \text{CO}(g) + \text{H}_2(g) \]
The particulate diagram below represents an equilibrium mixture of the system in a rigid container of volume \(V\).

The volume of the container is increased to \(3V\) at constant temperature \(T\), and the system is allowed to reach equilibrium. Which of the following particulate diagrams best represents the system after equilibrium is re-established in the larger volume?

A student investigates the heterogeneous gas-phase equilibrium shown below at a constant temperature \(T\).
\[ \text{C}(s) + \text{H}_2\text{O}(g) \rightleftharpoons \text{CO}(g) + \text{H}_2(g) \]
The particulate diagram below represents an equilibrium mixture of the system in a rigid container of volume \(V\).

The volume of the container is increased to \(3V\) at constant temperature \(T\), and the system is allowed to reach equilibrium. Which of the following particulate diagrams best represents the system after equilibrium is re-established in the larger volume?

![A legend box at the top maps four particle types: filled black square = \(\text{C}(s)\), open circle = \(\text{H}_2\text{O}\), filled black circle = \(\text{CO}\), and small gray circle = \(\text{H}_2\). Below the legend is a single rectangular container labeled \(V\). At the bottom of the container sits a horizontal layer containing exactly 6 filled black squares. In the gas space above the solid, there are exactly 4 open circles, exactly 2 filled black circles, and exactly 2 small gray circles, dispersed evenly. No other particles, labels, text, or annotations appear.](https://nerd-notes.com/wp-content/uploads/ubq-frq-generated/stem-fig-1-1790598659-hrQK2B.jpg)

- **A.** Diagram A
- **B.** Diagram B
- **C.** Diagram C
- **D.** Diagram D

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/123902/*