Heat of combustion

The heat of combustion, also called heating value or calorific value, is the amount of heat released when a specified amount of a fuel or other substance is completely burned with oxygen under standard conditions. It is usually measured in energy per mole, per unit mass or per unit volume of fuel. There are two conventional versions, the higher and lower heating value, which differ in whether the water produced by combustion is allowed to condense and give up its own heat; higher heating values are typically measured directly with a bomb calorimeter, while lower heating values are calculated from that data or from standard enthalpies of formation. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/