Chapter 8, Problem 8.95P

(a)

Interpretation Introduction

Interpretation:

The $\Delta E$ for the conversion of ${\text{F}}^{-}$ into ${\text{F}}^{+}$ with the help of Hess’s law is to be calculated.

Concept introduction:

Hess’s law is used to calculate the enthalpy change of an overall reaction that can be derived as a sum of two or more reaction. According to Hess’s law, $\Delta H$ of an overall reaction is equal to the sum of the enthalpy change for each individual reaction.

The formula for Hess’s law is as follows:

  $\Delta H_{\text{overall rxn}}=\Delta H_1+\Delta H_2+\mathrm{.......}+\Delta H_{\text{n}}$

Enthalpy is a state function so the value depends upon the initial state and final state not on the path so $\Delta H$ of an overall reaction can be calculated by the addition or subtraction of the individual steps whose $\Delta H$ is known.

(b)

Interpretation Introduction

Interpretation:

The $\Delta E$ for the conversion of ${\text{Na}}^{+}$ into ${\text{Na}}^{-}$ with the help of Hess’s law is to be calculated.

Concept introduction:

Hess’s law is used to calculate the enthalpy change of an overall reaction that can be derived as a sum of two or more reaction. According to Hess’s law $\Delta H$ of an overall reaction is equal to the sum of the enthalpy change for each individual reaction.

The formula for Hess’s law is as follows:

  $\Delta H_{\text{overall rxn}}=\Delta H_1+\Delta H_2+\mathrm{.......}+\Delta H_{\text{n}}$

Enthalpy is a state function so the value depends upon the initial state and final state not on the path so $\Delta H$ of an overall reaction can be calculated by the addition or subtraction of the individual steps whose $\Delta H$ is known.