---
title: "A student observes the particulate representations below representing a pure substance X undergoing a physical change in a sealed, rigid container of constant volume. Which of the following correctly compares the particle density and translational mobility of substance X in Box 2 relative to Box 1?"
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/119208/"
date_modified: "2026-08-19T12:39:21+00:00"
---

# A student observes the particulate representations below representing a pure substance X undergoing a physical change in a sealed, rigid container of constant volume. Which of the following correctly compares the particle density and translational mobility of substance X in Box 2 relative to Box 1?

A student observes the particulate representations below representing a pure substance X undergoing a physical change in a sealed, rigid container of constant volume. Which of the following correctly compares the particle density and translational mobility of substance X in Box 2 relative to Box 1?

![A legend at the top maps: solid gray circle = 1 molecule of substance X. Below the legend are two side-by-side rectangular containers of equal volume, labeled Box 1 and Box 2. Box 1 contains exactly 6 solid gray circles clustered together near the bottom of the container in close contact with one another. Box 2 contains exactly 6 solid gray circles widely separated from one another and distributed throughout the entire volume of the container. No other particles, labels, text, or annotations appear.](https://nerd-notes.com/wp-content/uploads/ubq-frq-generated/stem-fig-1-1787143161-HEDCRG.jpg)

- **A.** In Box 2, the particle density is lower and the translational mobility of the particles is greater than in Box 1.
- **B.** In Box 2, the particle density is higher and the translational mobility of the particles is greater than in Box 1.
- **C.** In Box 2, the particle density is lower and the translational mobility of the particles is smaller than in Box 1.
- **D.** In Box 2, the particle density is higher and the translational mobility of the particles is smaller than in Box 1.

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/119208/*