Chapter 7, Problem 7.72AP

Summary Introduction

To explain:

The differences in boiling points of heptanes and pentane.

Introduction:

The point where substance starts boiling and turns into vapor is called boiling point.

Pentane is an alkane of five carbon atoms, $\text{C}5\text{H}12$ is the chemical formula and $\text{CH}3\text{CH}2\text{CH}2\text{CH}2\text{CH}3$ is the structural formula.

Heptane is a straight chain alkane. Its chemical formula is $\text{C}7\text{H}17$ and structural formula is $\text{CH}3\text{CH}2\text{CH}2\text{CH}2\text{CH}2\text{CH}2\text{CH}3$.

Boiling point of pentane is $36°\text{C}$ and heptane’s boiling point is $98°\text{C}$.

The molecules that have strong bond with each other through intermolecular forces like hydrogen bond, weak London forces, covalent bonding do not achieve the kinetic energy, which is required to escape the liquid state. Hence molecules with strong intermolecular forces have higher boiling point.