Chapter 15, Problem 15.20P

Interpretation Introduction

Interpretation:

The molecules among ${\text{CCl}}_4$, ${\text{SiCl}}_4$, ${\text{SiBr}}_4$ and ${\text{CH}}_4$ has to be arranged in the order of their increasing molar enthalpy of vaporization.

Concept Introduction:

Molecules of liquid and solid are held together by a force of attraction. The value of enthalpy of vaporization and sublimation reflects the magnitude of force between the molecules. Greater the value of $\Delta H_{\text{vap}}$ or $\Delta H_{\text{sub}}$, greater will be the force of attraction between the molecules.

If a molecule has hydrogen bonds, it increases its molar enthalpies of vaporization because hydrogen bonds yield molar enthalpies of vaporization of $20–40\text{ kJ}\cdot {\text{mol}}^{\text{–1}}$, approximately.