Hess’s law states that total enthalpy change of a multi-step reaction is the same as the sum of the enthalpy changes of each step.
As an effect of Hess’s law:
- Reversing a reaction negates the values of (change in enthalpy), (change in entropy), and (change in Gibbs free energy).
- Scaling the coefficients of a reaction also scales the above thermodynamic values by the same scaling factor.