Chapter 10.3, Problem 3RQ

Interpretation Introduction

Interpretation: The Hess’s law and its uses need to be explained.

Concept introduction: The change in enthalpy at constant pressure is equal to the heat that flows as a form of energy.

  $\Delta H_p=\text{Heat}$

Here, p indicates that the process occurred in the condition of constant pressure.

Answer to Problem 3RQ

Hess’s law indicates that enthalpy is a state function.

Explanation of Solution

Hess's law states that the enthalpy change in moving from a set of reactants to a set of products does not depend on the number of steps in the reaction. So, enthalpy change does not dependent of the pathway of the process.

Hess's law helps to calculate heat of reaction which is difficult to measure in calorimeter directly.

Conclusion

In a given process, enthalpy change does not depend of the pathway.