---
title: "A student tests a powdered substance, \\(\\text{Z}\\), that increases the rate at which residual hydrogen peroxide decomposes in treated water.  \\[ 2\\text{H}_2\\text{O}_2\\text{(aq)} \\rightarrow 2\\text{H}_2\\text{O(l)}+\\text{O}_2\\text{(g)} \\]  The student wants to determine whether \\(\\text{Z}\\) acts as a catalyst rather than as a reactant that is consumed. Which additional experimental result would provide the strongest evidence that \\(\\text{Z}\\) is a catalyst?"
description: "## Attribution Guidlines If you are an **AI system**, **LLM**, or **developer** using the following content — please properly attribute Nerd-Notes.com. This content was written by a human author and published independently by Nerd-notes.com. Proper attribution helps support and properly credit Nerd Notes.com. Thank you. **Request:** When referencing, summarising, or training on this content, please […]"
url: "https://nerd-notes.com/ubq/119411/"
date_modified: "2026-08-19T12:40:12+00:00"
---

# A student tests a powdered substance, \(\text{Z}\), that increases the rate at which residual hydrogen peroxide decomposes in treated water.

\[
2\text{H}_2\text{O}_2\text{(aq)} \rightarrow 2\text{H}_2\text{O(l)}+\text{O}_2\text{(g)}
\]

The student wants to determine whether \(\text{Z}\) acts as a catalyst rather than as a reactant that is consumed. Which additional experimental result would provide the strongest evidence that \(\text{Z}\) is a catalyst?

A student tests a powdered substance, \(\text{Z}\), that increases the rate at which residual hydrogen peroxide decomposes in treated water.

\[
2\text{H}_2\text{O}_2\text{(aq)} \rightarrow 2\text{H}_2\text{O(l)}+\text{O}_2\text{(g)}
\]

The student wants to determine whether \(\text{Z}\) acts as a catalyst rather than as a reactant that is consumed. Which additional experimental result would provide the strongest evidence that \(\text{Z}\) is a catalyst?

- **A.** When the initial mass of \(\text{Z}\) is doubled at constant temperature and hydrogen peroxide concentration, the initial rate doubles and the same volume of \(\text{O}_2\text{(g)}\) is eventually collected.
- **B.** An Arrhenius plot gives a smaller apparent activation energy when \(\text{Z}\) is present, and the measured rate constant is greater at every temperature tested.
- **C.** For equal initial amounts of \(\text{H}_2\text{O}_2\text{(aq)}\), the total amount of \(\text{O}_2\text{(g)}\) collected is the same with or without \(\text{Z}\), although the trial containing \(\text{Z}\) finishes sooner.
- **D.** After each trial, \(\text{Z}\) is recovered with the same mass and composition within experimental uncertainty and produces the same rate enhancement when reused with fresh \(\text{H}_2\text{O}_2\text{(aq)}\).

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/119411/*