Latent Heat


Latent heat is the energy released or absorbed by a body or a thermodynamic system during a constant-temperature process. A typical example is a change of state of matter, meaning a phase transition such as the melting of ice or the boiling of water. A specific latent heat (L) expresses the amount of energy in the form of heat (Q) required to completely effect a phase change of a unit of mass (m), usually 1kg, of a substance as an intensive property. Intensive properties are material characteristics and are not dependent on the size or extent of the sample. The latent heat for a given mass of a substance is calculated by the mass of the substance and the specific latent heat for the particular substance.

Related formulas


Qamount of energy released or absorbed during the change of phase of the substance (kJ)
mmass of the substance (kg)
Lspecific latent heat for a particular substance, either Lf for fusion, or Lv for vaporization. (kJ/kg)