Chapter 12, Problem 56E

Interpretation Introduction

Interpretation:

The reason for the disappearance of solid ${\text{CO}}_2$ directly to gas, without coming into molten form is to be explained.

Concept Introduction:

Solid, liquid and gas are the three states of the matter. Their existence depends on the prevailing intermolecular forces. If the forces are very strong, the molecule exists as a solid at room temperature.

When these forces start decreasing, the state changes from solid to liquid. This is termed as melting. On further decrease in the intermolecular forces, liquid changes to a gas. This is termed as vaporization. Some substances bypass the liquid state and directly convert from solid state to gaseous state. This process is known as sublimation.

There is a number of intermolecular forces which play a role in different molecules such as dipole-dipole, hydrogen bonding, and dispersion forces.

The compounds lacking specific functional moieties have dispersion forces acting on their molecules. These increase with an increase in the molecular mass.

Lower are the forces of attraction, more is the volatility of the substance.