Why does temperature remain constant during a change of state?

The correct answer is Because energy is used to change potential energy.

Application lens: Apply the rule to the specific sample or situation instead of reciting a broad fact. This question asks: Why does temperature remain constant during a change of state. The correct response is Because energy is used to change potential energy, because specific heat capacity links energy, mass, material and temperature change. In Temperature changes in a system and specific heat capacity, the marking point should connect directly to describe why insulation is used in specific heat capacity experiments. 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 Internal energy and energy transfers, 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 343 is distinct because it uses this exact question context and the application lens rather than a generic particle-model sentence.