Phase transitions

A2 Physics

The latent heat, L, of a substance is the energy needed to change the state of a unit mass. This is measured in Jkg-1.

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There is no temperature change until the substance has changed state completely.

There are three types of latent heat:

blank spaceFusion: between solid and liquid

blank spaceVaporisation: between liquid and gas

blank spaceSublimation: between solid and gas

So when a substance is heated, the temperature changes until it reaches the latent heat, then remains at the same temperature until all of it has changed state:

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Back to Contents: Physics: Thermodynamics

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