Chapter 19, Problem 19.73SP

Interpretation Introduction

Interpretation:

The standard cell potential for the reaction in a fuel cell that uses the reaction ${\text{CH}}_{\text{4(g)}}{\text{+2O}}_{\text{2(g)}}\to {\text{CO}}_{\text{2(g)}}{\text{+2H}}_{\text{2}}{\text{O}}_{\text{(g)}}$ is to be calculated.

Introduction:

The cell potential of a certain electrochemical cell states how much voltage generates between two half cells of that electrochemical cell. We can denote the cell potential as $E^0$. On the other hand, the free energy change or $\Delta G^0$ is a thermodynamic quantity that describes the internal energy of the electrochemical cell which is available to generate electricity. There is a relationship between cell potential and free energy change as follows:

$\Delta G^0=-nF{E}^0$

Where, $n$ is the number of moles of electrons that transfer during the reaction while $F$ is the Faraday Constant.

We can calculate the standard cell potential using the standard free energies of formation ( $\Delta G^0{}_f$ ) of reactants and products of a given reaction. The equation for this calculation is

$\Delta G^0=[\Delta G^0{}_f(Reactants)]-[\Delta G^0{}_f(Products)]$