Why does gas pressure increase when the volume of a gas decreases at constant temperature (Particle motion in gases)

The correct answer is Particles collide more often due to reduced space.

Comparison lens: State both sides of the comparison so the contrast is explicit rather than implied. This question asks: Why does gas pressure increase when the volume of a gas decreases at constant temperature (Particle motion in gases). The correct response is Particles collide more often due to reduced space, because density links mass and volume, so the answer must preserve which quantity is being calculated. In Particle motion in gases, the marking point should connect directly to use the particle model to explain why gas pressure increases when temperature increases at constant volume. If the question includes values, the working must keep the appropriate unit and operation; if it is an explanation, it must name the relevant particle behaviour or energy change. This item belongs to Particle model and pressure, so avoid answers that switch to a different quantity, confuse heat with temperature, or describe gas pressure without collisions when collisions are the reason. Checkpoint 497 is distinct because it uses this exact question context and the comparison lens rather than a generic particle-model sentence.