Latent heat of vaporization is the amount of heat required to change a liquid into a vapour.

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Latent heat of vaporization is the amount of heat required to change a liquid into a vapour.

Latent heat of vaporization is the amount of heat required to change a liquid into a vapour. This energy is needed to overcome the intermolecular forces holding the liquid together, allowing molecules to break free into the gas phase. Temperature stays constant during this phase change at the boiling point because all the added heat goes into changing the phase, not warming the substance. The other ideas describe different processes: heat released during condensation is the reverse process, heating a solid to its melting point is sensible heat used to raise temperature until melting, and cooling a gas involves removing heat, also sensible rather than latent energy. So the statement that matches the concept is the amount of heat required to change a liquid into a vapour.

Latent heat of vaporization is the amount of heat required to change a liquid into a vapour. This energy is needed to overcome the intermolecular forces holding the liquid together, allowing molecules to break free into the gas phase. Temperature stays constant during this phase change at the boiling point because all the added heat goes into changing the phase, not warming the substance. The other ideas describe different processes: heat released during condensation is the reverse process, heating a solid to its melting point is sensible heat used to raise temperature until melting, and cooling a gas involves removing heat, also sensible rather than latent energy. So the statement that matches the concept is the amount of heat required to change a liquid into a vapour.

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