Chapter 6, Problem 61E

Propane, ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{3}}\text{,}$ is a gas at room temperature, whereas propanol, ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CH}}_{\text{2}}\text{OH,}$ is a liquid. Why the difference?