What is the relationship between pressure and volume for a fixed mass of gas at constant temperature (Increasing the pressure of a gas (physics only) (HT only))

The correct answer is Pressure is inversely proportional to volume..

Boundary lens: Keep this separate from nearby specification points that use similar words but test a different idea. This question asks: What is the relationship between pressure and volume for a fixed mass of gas at constant temperature (Increasing the pressure of a gas (physics only) (HT only)). The correct response is Pressure is inversely proportional to volume., because density links mass and volume, so the answer must preserve which quantity is being calculated. In Increasing the pressure of a gas (physics only) (HT only), the marking point should connect directly to (Physics only) (HT only) Distinguish temperature increase during compression from pressure increase caused by reduced 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 622 is distinct because it uses this exact question context and the boundary lens rather than a generic particle-model sentence.