Write the balanced chemical equation for the formation of 1 mole of the compound from its elements in their standard states
Use the formula: ΔH°f = ΣΔH°f(products) − ΣΔH°f(reactants)
For an element in its standard state, ΔH°f = 0
Multiply each substance’s standard enthalpy of formation by its stoichiometric coefficient
Add the values for all products
Add the values for all reactants
Subtract the total reactants value from the total products value
Express the result in kJ mol⁻¹