Heat of combustion, also known as the enthalpy of combustion or calorific value, is the amount of energy released during the combustion of a chemical compound such as a fuel, when it reacts completely with oxygen, under standard conditions. It is typically expressed in joules per mole (J/mol) or kilojoules per mole (kJ/mol) and is often used to compare the efficiency of different fuels. The heat of combustion is usually a negative value, indicating that energy is released during the process.
