Specific Latent Heat

This lesson explains specific latent heat, the difference between latent heat of fusion and latent heat of vaporisation, and how these concepts relate to heating curves. This is a required equation for the Edexcel GCSE Combined Science specification (1SC0).

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What Is Latent Heat?

When a substance changes state (e.g. melting or boiling), energy is transferred to break or form bonds between particles. During this process:

• The temperature stays constant.
• The energy goes into changing the potential energy of the particles (not their kinetic energy).

This energy is called latent heat (from the Latin latere, meaning "to hide") because the energy is "hidden" — it does not cause a temperature change.

$E = m L$E=mL

Symbol	Quantity	Unit
$E$E	Energy transferred	joules (J)
$m$m	Mass	kilograms (kg)
$L$L	Specific latent heat	joules per kilogram (J/kg)

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Two Types of Specific Latent Heat