# Latent heat

Latent heat (kJ/mol) is the change of total heat energy involved in phase changes. Three types of latent heat are involved: latent heat of fusion, latent heat of evaporation, and latent heat of sublimation.

**Latent heat of fusion**

Latent heat of fusion or enthalpy of fusion (Δ_H__{fus}) is the amount of heat required to change one mole of a substance from the solid state to the liquid state.

**Latent heat of evaporation**

Latent heat of evaporation or enthalpy of evaporation (Δ_H__{vap}) is the amount of heat required to change one mole of a substance from the liquid state to the gas state.

The enthalpy of sublimation can be estimated as the sum of its enthalpy of fusion and vaporization.