Describe what happens to the internal energy of a gas when work is done on it.

When work is done on a gas, its internal energy increases. This is because the energy from the work done is transferred to the gas particles, increasing their kinetic energy and thus raising the temperature of the gas.

Evidence lens: Use the data, graph feature, practical observation, or particle behaviour that proves the answer. This question asks: Describe what happens to the internal energy of a gas when work is done on it. The correct response is When work is done on a gas, its internal energy increases. This is because the energy from the work done is transferred to the gas particles, increasing their kinetic energy and thus raising the temperature of the gas., because gas pressure comes from particle collisions with container walls. In Increasing the pressure of a gas (physics only) (HT only), the marking point should connect directly to (Physics only) (HT only) Explain that doing work on a gas transfers energy to the gas. 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 585 is distinct because it uses this exact question context and the evidence lens rather than a generic particle-model sentence.