A thermochemical equation is a balanced stoichiometric chemical equation that includes the enthalpy change (∆H).
Conventions adopted in thermochemical equations:
1. The coefficients in a balanced thermochemical equation refer to number of moles of reactants and products involved in the reaction.
2. The enthalpy change of the reaction ∆H has unit kJ.
3. When the chemical reaction is reversed, the value of AR is reversed in sign with the same magnitude.
4. Physical states (gas, liquid, aqueous and solid) of all species is important and must be specified in a thermochemical reaction since AH depends on the phases of reactants and products.
5. if the thermochemical equation is multiplied throughout by a number, the enthalpy change is also be multiplied by the same number value.
6. The negative sign of ∆H indicates the reaction to be an exothermic and the positive sign of ∆H indicates an endothermic type of reaction.
