How to calculate the enthalpy of combustion for a given substance?

To calculate the enthalpy of combustion for a substance, you need to determine the amount of heat released when one mole of the substance is completely burned in oxygen. This can be done by subtracting the sum of the enthalpies of formation of the products from the sum of the enthalpies of formation of the reactants. The enthalpy of combustion is typically expressed in kilojoules per mole.