---
title: "A student investigates the decomposition of a reactant, \\(\\text{A(aq)}\\), at a constant temperature according to the balanced equation below.  \\[ 2\\,\\text{A(aq)} \\rightarrow \\text{B(aq)} + 2\\,\\text{C(g)} \\]  The initial concentration of \\(\\text{A(aq)}\\) is \\(0.80\\text{ M}\\). After \\(60\\text{ s}\\), the concentration of \\(\\text{A(aq)}\\) is measured to be \\(0.20\\text{ M}\\). What is the average rate of disappearance of \\(\\text{A(aq)}\\) over this \\(60\\text{ s}\\) time interval?"
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url: "https://nerd-notes.com/ubq/119647/"
date_modified: "2026-08-21T08:11:55+00:00"
---

# A student investigates the decomposition of a reactant, \(\text{A(aq)}\), at a constant temperature according to the balanced equation below.

\[ 2\,\text{A(aq)} \rightarrow \text{B(aq)} + 2\,\text{C(g)} \]

The initial concentration of \(\text{A(aq)}\) is \(0.80\text{ M}\). After \(60\text{ s}\), the concentration of \(\text{A(aq)}\) is measured to be \(0.20\text{ M}\). What is the average rate of disappearance of \(\text{A(aq)}\) over this \(60\text{ s}\) time interval?

A student investigates the decomposition of a reactant, \(\text{A(aq)}\), at a constant temperature according to the balanced equation below.

\[ 2\,\text{A(aq)} \rightarrow \text{B(aq)} + 2\,\text{C(g)} \]

The initial concentration of \(\text{A(aq)}\) is \(0.80\text{ M}\). After \(60\text{ s}\), the concentration of \(\text{A(aq)}\) is measured to be \(0.20\text{ M}\). What is the average rate of disappearance of \(\text{A(aq)}\) over this \(60\text{ s}\) time interval?

- **A.** \(3.3 \times 10^{-3}\text{ M}\cdot\text{s}^{-1}\)
- **B.** \(5.0 \times 10^{-3}\text{ M}\cdot\text{s}^{-1}\)
- **C.** \(1.0 \times 10^{-2}\text{ M}\cdot\text{s}^{-1}\)
- **D.** \(1.3 \times 10^{-2}\text{ M}\cdot\text{s}^{-1}\)

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/119647/*