How much energy is needed to melt 0.5 kg of ice at 0°C, given that the specific latent heat of fusion of ice is 334,000 J/kg (Changes of state and specific latent heat)

The correct answer is 167,000 J.

Comparison lens: State both sides of the comparison so the contrast is explicit rather than implied. This question asks: How much energy is needed to melt 0.5 kg of ice at 0°C, given that the specific latent heat of fusion of ice is 334,000 J/kg (Changes of state and specific latent heat). The correct response is 167,000 J, because density links mass and volume, so the answer must preserve which quantity is being calculated. In Changes of state and specific latent heat, the marking point should connect directly to calculate mass when energy transferred and specific latent heat are known. 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 401 is distinct because it uses this exact question context and the comparison lens rather than a generic particle-model sentence.