Chapter 5.3, Problem 1PPC

Interpretation Introduction

Interpretation:

The enthalpy change of the given reaction is to be calculated.

Concept introduction:

The change in enthalpy of a reaction, when reactants are converted to products, is the same whether the reaction takes place in one step or multiple steps. This law is known as Hess’s law.

For any process, the change in enthalpy is given by expression:

$\Delta \text{H}\text{}\text{=}\Delta \text{U}\text{}+\Delta \left(\text{PV}\right)$

Here, $\Delta \text{H}\text{}$ is change in enthalpy, $\Delta \text{U}$ is change in internal enthalpy, $\text{P}$ is pressure, and $\text{V}$ is volume.

If pressure is constant, the change in enthalpy is given by expression: $\Delta \text{H}\text{}\text{=}\Delta \text{U}\text{}+\text{P}\Delta \text{V}$.

On reversing any equation, the sign of enthalpy changes.