Chapter 4, Problem 4.11YT

Interpretation Introduction

Interpretation:

The heat of combustion of cyclooctane is 4962.2 kJ/mol (1186.0 kcal/mol). The number of ${\text{CH}}_{\text{2}}$ groups in cyclooctane is to be determined. The ring strain per ${\text{CH}}_{\text{2}}$ group is to be computed by subtracting cyclohexane’s heat of combustion per ${\text{CH}}_{\text{2}}$ group from that determined for cyclooctane. The total ring strain for cyclooctane is to be computed by taking into account the total number of ${\text{CH}}_{\text{2}}$ groups in the molecule. These values are to be compared to those for the other molecules in Table 4-1.

Concept introduction:

Any difference in the heat of combustion per ${\text{CH}}_{\text{2}}$ group for two cyclic alkanes reflects a difference in ring strain per ${\text{CH}}_{\text{2}}$ group. The total ring strain is obtained by multiplying the strain per ${\text{CH}}_{\text{2}}$ group by the number of ${\text{CH}}_{\text{2}}$ groups.