---
title: "A sample of an ideal gas is confined in a rigid-walled cylinder fitted with a movable piston at a constant temperature of \\(298\\text{ K}\\). The piston is slowly pushed downward, decreasing the volume of the gas from \\(2.0\\text{ L}\\) (State 1) to \\(1.0\\text{ L}\\) (State 2), as represented in the diagrams below.  Based on the representations and the principles of kinetic molecular theory, which of the following best explains why the pressure exerted by the gas in State 2 is greater than the pressure in State 1?"
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url: "https://nerd-notes.com/ubq/123698/"
date_modified: "2026-09-28T12:02:01+00:00"
---

# A sample of an ideal gas is confined in a rigid-walled cylinder fitted with a movable piston at a constant temperature of \(298\text{ K}\). The piston is slowly pushed downward, decreasing the volume of the gas from \(2.0\text{ L}\) (State 1) to \(1.0\text{ L}\) (State 2), as represented in the diagrams below.

Based on the representations and the principles of kinetic molecular theory, which of the following best explains why the pressure exerted by the gas in State 2 is greater than the pressure in State 1?

A sample of an ideal gas is confined in a rigid-walled cylinder fitted with a movable piston at a constant temperature of \(298\text{ K}\). The piston is slowly pushed downward, decreasing the volume of the gas from \(2.0\text{ L}\) (State 1) to \(1.0\text{ L}\) (State 2), as represented in the diagrams below.

Based on the representations and the principles of kinetic molecular theory, which of the following best explains why the pressure exerted by the gas in State 2 is greater than the pressure in State 1?

![A two-panel grayscale diagram titled State 1 and State 2. A legend indicates: open circle = gas particle, straight arrow = particle velocity vector. State 1 shows a tall rectangular cylinder of volume \(2.0\text{ L}\) with a horizontal piston near the top. Inside State 1, there are exactly 6 open circles evenly distributed; each circle has an attached straight arrow of uniform length \(1.0\text{ cm}\) pointing in random directions. State 2 shows the identical cylinder with the piston positioned at half the original height, enclosing a volume of \(1.0\text{ L}\). Inside State 2, there are exactly 6 open circles evenly distributed in the smaller space; each circle has an attached straight arrow of the same uniform length \(1.0\text{ cm}\) pointing in random directions. The cylinder walls and piston are drawn with solid black lines. No other particles, labels, text, or annotations appear.](https://nerd-notes.com/wp-content/uploads/ubq-frq-generated/stem-fig-1-1790596920-G91d1x.jpg)

- **A.** The pressure increases because the average kinetic energy of the gas particles increases, resulting in a greater average force per collision with the container walls.
- **B.** The pressure increases because the frequency of particle collisions per unit area of the container walls increases, while the average force exerted per collision remains constant.
- **C.** The pressure increases because the gas particles are forced closer together, causing intermolecular repulsive forces to push the particles into the container walls with greater force.
- **D.** The pressure increases because the total number of gas particles inside the cylinder doubles, increasing the total number of wall collisions per second.

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/123698/*