1)When given enthalpies of Combustion.@CaRP {Enthalpy change=Enthalpy of combustion of reactants-Enthalpy of combustion of products} 2)When given enthalpies of Formation.@FLiPpeR{Enthalpy change=Enthalpy of Formation of products-Enthalpy of formation of reactants} 3)When given Bond enthalpies.@BuRp {Enthalpy change=Bond enthalpies of reactants-Bond enthalpies of product} 4)When calculating Entropy change.@SliPpeR {Entropy change=Entropy of products-Entropy of reactants} 5)Equation for free energy change.@Gibbs HaTS{∆G=∆H-T∆S}