Why does temperature remain constant during a change of state?

The correct answer is Energy transferred changes particle potential energy rather than average kinetic energy.

Cause lens: Name the cause, then state the effect on particles, pressure, density, or energy. This question asks: Why does temperature remain constant during a change of state. The correct response is Energy transferred changes particle potential energy rather than average kinetic 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 define specific heat capacity as the energy needed to raise the temperature of one kilogram of a substance by one degree Celsius. 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 280 is distinct because it uses this exact question context and the cause lens rather than a generic particle-model sentence.