Chapter 18, Problem 18.74QE

a)

Interpretation Introduction

Interpretation:

Oxidation and reduction half-reactions have to be given for the reaction shown below:

  ${\text{CH}}_4\text{(g) +2}{\text{O}}_{\text{2}}\left(\text{g}\right)\to {\text{CO}}_{\text{2}}\text{(g)}\text{+2}{\text{H}}_2\text{O(l)}$

Concept introduction:

Steps for balancing half –reactions in BASIC solution:

• Balance all atoms except H and O in half reaction.
• Balance O atoms by adding water to the side missing O atoms.
• Balance the H atoms by adding ${\text{H}}^{\text{+}}$ to the side missing H atoms.
• Balance the charge by adding electrons to side with more total positive charge.
• Make the number of electrons the same in both half reactions by multiplication, while avoiding fractional number of electrons.
• Add the same numbers of ${\text{OH}}^{\text{-}}$ groups as there are ${\text{H}}^{\text{+}}$ present to both sides of the equation.

b)

Interpretation Introduction

Interpretation:

The potential of the cell has to be determined from standard free energy change.

c)

Interpretation Introduction

Interpretation:

Number of kilojoules of electrical energy produced when one gram of methane is consumed has to be determined.