Standard enthalpy change of combustion

The standard enthalpy of combustion is the enthalpy change when one mole of a substance completely reacts with oxygen under standard thermodynamic conditions (although experimental values are usually obtained under different conditions and subsequently adjusted). By definition, combustion reactions are generally strongly exothermic and so enthalpies of combustion are generally strongly negative.

Additional recommended knowledge

How to ensure accurate weighing results every day?

Weighing the right way

Safe Weighing Range Ensures Accurate Results

It is commonly denoted as or

Enthalpies of combustion are typically measured using bomb calorimetry, and have units of energy (typically kJ); strictly speaking, the enthalpy change per mole of substance combusted is the standard molar enthalpy of combustion (which typically would have units of kJ mol⁻¹).