Specific Latent Heat

Think of specific latent heat as the energy price tag for changing states - it's exactly how much energy you need to transform 1kg of a material from one state to another (like solid to liquid) without the temperature budging at all.

There are two main types you need to know. Specific latent heat of fusion handles the energy needed between solid and liquid states - think ice melting into water or water freezing into ice. Specific latent heat of vaporisation deals with the liquid-to-gas transformation, like water boiling into steam or steam condensing back to water.

The calculation is brilliantly simple: Energy = mass × specific latent heat. So if water's specific latent heat of vaporisation is 2,260,000 J/kg, then boiling 1.5kg of water needs 2,260,000 × 1.5 = 3,390,000 J of energy.

Quick Check: During state changes, all the energy goes into breaking or forming bonds between particles - that's why temperature stays constant even though you're pumping in loads of energy!