A 2 kg block of ice is heated until it melts completely. If the specific latent heat of fusion for ice is 334,000 J/kg, calculate the energy required to melt the ice (Changes of state and specific latent heat)

668,000 J

Practical lens: Link apparatus, readings, and uncertainty to the exact measurement named in the objective. This question asks: A 2 kg block of ice is heated until it melts completely. If the specific latent heat of fusion for ice is 334,000 J/kg, calculate the energy required to melt the ice (Changes of state and specific latent heat). The correct response is 668,000 J, because changes of state are explained by particle energy and arrangement. In Changes of state and specific latent heat, the marking point should connect directly to explain that energy transferred during a change of state changes particle potential energy rather than average kinetic energy. 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 422 is distinct because it uses this exact question context and the practical lens rather than a generic particle-model sentence.