Limitations of the kinetic theory of gases

Question 1

define an ideal gas

Answer 1

An ideal gas is one that perfectly obeys all the assumptions of the kinetic theory of gases under all conditions of temperature and pressure

Question 2

Define real gases

Answer 2

Real gases differ from ideal gases because (i) forces of attraction and repulsion do exist between the molecules and (ii) the volume of the molecules is not negligible

Question 3

What is the limitation of the following assumption:

There are no attractive or repulsive forces between the molecules of a gas.

Answer 3

All real gases do have tiny attractive or repulsive forces between the molecules of the gas. Gas molecules that are polar will have attractive intermolecular forces because the partially negative end of one molecule will be attracted to the partially positive end of another molecule.

Question 4

When do real gases come close to ideal gas behaviour?

Answer 4

At low pressure when the molecules are widely spaced.

At high temperatures when the molecules are moving rapidly, preventing the forces between molecules from operating.

Question 5

Why does diffusion occur?

Answer 5

Diffusion occurs because gases consist of particles that have a great deal of freedom and are always on the move.