Chapter 8, Problem 69A

Interpretation Introduction

Interpretation: The amount of energy required to dissociate all C-H bonds in 1 mol of methane needs to be determined.

Concept Introduction: The strength of intermolecular interactions depends on the type of bonding between two atoms. The amount of energy required to break the bond is directly proportional to its strength.

Explanation of Solution

In 1 mol of methane $\left({\text{CH}}_{\text{4}}\right)$ , there are 4 C-H bonds. The bond dissociation energy for the C-H bond is 432.4 kJ/mol. The energy required to break all the bonds will be four times the bond dissociation energy for the C-H bond. Thus, the energy required can be calculated as follows:

  $\begin{array}{c}E=\left(4\text{ mol}\right)\left(432.4\text{ kJ/mol}\right)\\ =1729.6\text{ kJ}\end{array}$

Thus, the amount of energy required to dissociate all C-H bonds is 1729.6 kJ.