Specific latent heat

The latent heat for one kilogram is the specific latent heat. Its unit is J kg^-1.

Specific latent heat of fusion

The heat needed to turn a unit mass of a solid at its melting point completely into liquid, with no change in temperature.

For ice: 1 kg of ice at 0 °C needs 3.36 × 10⁵ J to become water at 0 °C.

Specific latent heat of vaporization

The heat needed to turn a unit mass of a liquid at its boiling point completely into vapour, with no change in temperature.

For water: 1 kg of water at 100 °C needs 2.26 × 10⁶ J to become steam at 100 °C.

Figure to be added

Figures 9.14 and 9.15 — 1 kg of ice at 0 °C taking in 3.36 × 10⁵ J to become 1 kg of water at 0 °C; 1 kg of water at 100 °C taking in 2.26 × 10⁶ J to become 1 kg of steam.

Turning water into steam takes almost seven times as much heat as melting the same mass of ice.