13.1 A Model to Explain Gas Behavior

The Nature of Gases• Air is a mixture of gases• Gases will occupy the volume

available to them• Gases can be compressed• Regardless of their identity, all gases

exhibit remarkably similar physical behavior

• At 0 C° and 1 atm pressure, one mole any gas will occupy 22.4 L.

Physical Properties of all Gases• Gases have mass.• It is easy to compress gases.• Gases fill their container completely.• Different gases can move through

each other rapidly (diffusion).• Gases exert pressure.• The pressure of a gas depends on

its temperature.

Kinetic-Molecular Theory1. A gas consists of very small

particles, each of which has a mass.

2. The distance separating particles in a gas is very large, therefore the volume the actual particles occupy is negligible.

3. Gas particles are in constant rapid, random motion.

Kinetic-Molecular Theory

4. Collision between gas particles or between a gas particle and the container are elastic.

5. Temperature depends on average kinetic energy.

6. Gas particles exert no attractive forces between themselves.