Hess' Law

Hess' Law allows enthalpy change to be determined indirectly as it states that if a reaction can take place via two different routes with the starting and finishing conditions being the same then the total enthalpy change for each route is the same.

The law comes from the idea of conservation of energy and an enthalpy cycle shows the two routes by which the reaction can take to convert the reactants into products.

The whole principle of Hess…