---
title: "A student is provided with three separate samples of pure gaseous hydrocarbons, each having an identical mass of \\(10.0\\text{ g}\\): Sample 1 contains \\(\\text{CH}_4\\), Sample 2 contains \\(\\text{C}_2\\text{H}_6\\), and Sample 3 contains \\(\\text{C}_3\\text{H}_8\\). Which of the following correctly ranks the samples in order of the total number of moles of molecules, from greatest to least, and provides the correct justification?"
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url: "https://nerd-notes.com/ubq/120158/"
date_modified: "2026-08-21T16:02:40+00:00"
---

# A student is provided with three separate samples of pure gaseous hydrocarbons, each having an identical mass of \(10.0\text{ g}\): Sample 1 contains \(\text{CH}_4\), Sample 2 contains \(\text{C}_2\text{H}_6\), and Sample 3 contains \(\text{C}_3\text{H}_8\). Which of the following correctly ranks the samples in order of the total number of moles of molecules, from greatest to least, and provides the correct justification?

A student is provided with three separate samples of pure gaseous hydrocarbons, each having an identical mass of \(10.0\text{ g}\): Sample 1 contains \(\text{CH}_4\), Sample 2 contains \(\text{C}_2\text{H}_6\), and Sample 3 contains \(\text{C}_3\text{H}_8\). Which of the following correctly ranks the samples in order of the total number of moles of molecules, from greatest to least, and provides the correct justification?

- **A.** \(\text{Sample 3} > \text{Sample 2} > \text{Sample 1}\), because the number of moles is directly proportional to molar mass for a constant mass of substance, so the compound with the highest molar mass contains the greatest number of moles.
- **B.** \(\text{Sample 3} > \text{Sample 2} > \text{Sample 1}\), because each molecule of \(\text{C}_3\text{H}_8\) contains the greatest number of atoms per formula unit, yielding the greatest total number of moles of gas.
- **C.** \(\text{Sample 1} > \text{Sample 2} > \text{Sample 3}\), because the number of moles is inversely proportional to molar mass for a constant mass of substance, so the compound with the lowest molar mass contains the greatest number of moles.
- **D.** \(\text{Sample 1} > \text{Sample 2} > \text{Sample 3}\), because \(\text{CH}_4\) molecules have the smallest molecular size and occupy less individual volume, allowing more moles of gas to exist in the sample.

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/120158/*