If 500,000 J of energy is used to change the state of a 1.5 kg substance with a specific latent heat of vaporization of 333,000 J/kg, what is the mass of the substance that has changed state (Changes of state and specific latent heat)

1.5 kg

Method lens: First identify the measured quantity, then match the equation or particle idea to the command word. This question asks: If 500,000 J of energy is used to change the state of a 1.5 kg substance with a specific latent heat of vaporization of 333,000 J/kg, what is the mass of the substance that has changed state (Changes of state and specific latent heat). The correct response is 1.5 kg, 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 404 is distinct because it uses this exact question context and the method lens rather than a generic particle-model sentence.