Standard enthalpy of Combustion is the enthalpy change when one mole of a substance is totally combusted in oxygen, and is measured at 298K and 1 atmospheric pressure.

The standard enthalpy change of combustion is commonly denoted as $\backslash Delta\; H\; ^\{\backslash circ\}\; \_\{comb\}$ or $\backslash Delta\; H\; ^\{\backslash circ\}\; \_\{c\}$

Standard enthalpy changes of combustion are always negative as combustion always releases energy to the surroundings.

In practice it is impossible to carry out combustion under the standard conditions of 298K and 1 atmospheric pressure, so adjustments are made to values after combustion is carried out normally.

The enthalpy of combustion is measured in kilojoules per mole (kJ/mol), ie the amount of energy produced (in kJ) for every mole of the substance.

=See Also=

• NIST Chemistry WebBook

Enthalpy