Specific Latent Heat

This lesson covers specific latent heat, the energy required to change the state of a substance without changing its temperature. This is a key concept in the AQA GCSE Combined Science Trilogy specification (8464, section 6.3.1).

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What Is Latent Heat?

Latent heat is the energy needed to change the state of a substance without changing its temperature. The word "latent" means "hidden" — the energy is hidden because there is no temperature change even though energy is being supplied (or released).

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The Equation

$E = m \times L$E=m×L

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

Exam Tip: The specific latent heat equation $E = mL$E=mL is given on the AQA equation sheet. You do not need to memorise it, but you must be able to use and rearrange it correctly.

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Two Types of Specific Latent Heat