What happens to the particles in a liquid during boiling?

The correct answer is They gain enough energy to escape into the gas phase..

Method lens: First identify the measured quantity, then match the equation or particle idea to the command word. This question asks: What happens to the particles in a liquid during boiling. The correct response is They gain enough energy to escape into the gas phase., because changes of state are explained by particle energy and arrangement. In Changes of state, the marking point should connect directly to distinguish boiling from evaporation using where and how the change occurs. 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 Changes of state and the particle model, 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 164 is distinct because it uses this exact question context and the method lens rather than a generic particle-model sentence.