Hess’s Law is related to which concept in thermochemistry?

Explanation

Hess’s Law states that the total enthalpy change for a reaction is the same regardless of the pathway taken. You can add up enthalpy changes from multiple steps to find the overall reaction enthalpy.

This law allows chemists to calculate enthalpy changes for reactions that are difficult to measure directly. Breaking a reaction into simpler steps makes calculations easier.

For example, if going from A to C directly is hard to measure, you can measure A to B and B to C separately, then add them together. The total equals the direct A to C change.