According to Hess's law, what can be said about the standard enthalpy of an overall reaction?

Hess's law states that the total enthalpy change for a reaction is the same, regardless of the number of steps the reaction takes. This means that the standard enthalpy of an overall reaction can be calculated as the sum of the standard enthalpies of the individual reactions that lead to the same final products from the same initial reactants.

This principle reflects the path independence of enthalpy, which is a state function. Therefore, when you add together the enthalpy changes of the individual steps (or reactions), the resulting value gives the net enthalpy change for the overall reaction. This approach is particularly useful when direct measurement of a reaction's enthalpy change is difficult, allowing for the calculation using other known values.

As a result, the assertion that the standard enthalpy of an overall reaction is the sum of the standard enthalpies of the individual reactions is a direct application of Hess's law and accurately captures the concept of enthalpy being a state function that is independent of the specific pathway taken during a reaction sequence.