J/kg

joule per kilogram

Specific latent heatexact by definition

The joule per kilogram is the SI unit of specific latent heat, the energy absorbed or released per kilogram when a substance changes phase at constant temperature. It is the coherent SI combination, so the factor of 1 is exact. The same unit serves for latent heat of fusion, vaporisation and sublimation.

Watch out: Latent heat is absorbed with no change in temperature, which is exactly why it does not appear on a thermometer. This is the reason a pot of water sits at 100 °C for many minutes before it boils dry, and the reason a steam burn is far worse than a hot-water burn at the same temperature.

1 J/kg 1 J/kg