A 2.0 kg sample of liquid water at 100 °C is boiled until all of it becomes steam at 100 °C. If the specific latent heat of vaporisation of water is 2.26 × 10⁶ J kg⁻¹, what is the energy transferred (Changes of state and specific latent heat)

The correct answer is 4.52 × 10⁷ J.

Cause lens: Name the cause, then state the effect on particles, pressure, density, or energy. This question asks: A 2.0 kg sample of liquid water at 100 °C is boiled until all of it becomes steam at 100 °C. If the specific latent heat of vaporisation of water is 2.26 × 10⁶ J kg⁻¹, what is the energy transferred (Changes of state and specific latent heat). The correct response is 4.52 × 10⁷ 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 424 is distinct because it uses this exact question context and the cause lens rather than a generic particle-model sentence.