---
title: "The decomposition of gaseous \\(\\text{X}\\) proceeds according to the balanced equation below: \\[ 2\\,\\text{X}(g) \\rightarrow \\text{Y}(g) + \\text{Z}(g) \\] A sample of pure \\(\\text{X}(g)\\) is placed into a rigid \\(1.0\\text{ L}\\) vessel at a constant temperature. The particulate diagrams below represent the contents of the vessel at three successive times: \\(t = 0\\text{ s}\\), \\(t = 100\\text{ s}\\), and \\(t = 200\\text{ s}\\). Each particle represents \\(1.0 \\times 10^{-3}\\text{ mol}\\) of the indicated substance.  Based on the representations, what is the order of the reaction with respect to \\(\\text{X}\\), and what is the value of the rate constant \\(k\\)?"
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url: "https://nerd-notes.com/ubq/123711/"
date_modified: "2026-09-28T12:02:05+00:00"
---

# The decomposition of gaseous \(\text{X}\) proceeds according to the balanced equation below:
\[ 2\,\text{X}(g) \rightarrow \text{Y}(g) + \text{Z}(g) \]
A sample of pure \(\text{X}(g)\) is placed into a rigid \(1.0\text{ L}\) vessel at a constant temperature. The particulate diagrams below represent the contents of the vessel at three successive times: \(t = 0\text{ s}\), \(t = 100\text{ s}\), and \(t = 200\text{ s}\). Each particle represents \(1.0 \times 10^{-3}\text{ mol}\) of the indicated substance.

Based on the representations, what is the order of the reaction with respect to \(\text{X}\), and what is the value of the rate constant \(k\)?

The decomposition of gaseous \(\text{X}\) proceeds according to the balanced equation below:
\[ 2\,\text{X}(g) \rightarrow \text{Y}(g) + \text{Z}(g) \]
A sample of pure \(\text{X}(g)\) is placed into a rigid \(1.0\text{ L}\) vessel at a constant temperature. The particulate diagrams below represent the contents of the vessel at three successive times: \(t = 0\text{ s}\), \(t = 100\text{ s}\), and \(t = 200\text{ s}\). Each particle represents \(1.0 \times 10^{-3}\text{ mol}\) of the indicated substance.

Based on the representations, what is the order of the reaction with respect to \(\text{X}\), and what is the value of the rate constant \(k\)?

- **A.** Zero order, and \(k = 4.0 \times 10^{-5}\text{ M}\cdot\text{s}^{-1}\)
- **B.** First order, and \(k = 6.9 \times 10^{-3}\text{ s}^{-1}\)
- **C.** First order, and \(k = 1.0 \times 10^{-2}\text{ s}^{-1}\)
- **D.** Second order, and \(k = 1.25\text{ M}^{-1}\cdot\text{s}^{-1}\)

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/123711/*