Assumptions of the Kinetic Theory of Gases
- Gases consist of atoms or molecules randomly moving around at high speeds
- The kinetic theory of gases models the thermodynamic behaviour of gases by linking the microscopic properties of particles (mass and speed) to macroscopic properties of particles (pressure and volume)
- The theory is based on a set of the following assumptions:
- Molecules of gas behave as identical, hard, perfectly elastic spheres
- The volume of the molecules is negligible compared to the volume of the container
- The time of a collision is negligible compared to the time between collisions
- There are no forces of attraction or repulsion between the molecules
- The molecules are in continuous random motion
- The number of molecules of gas in a container is very large, therefore the average behaviour (eg. speed) is usually considered
Exam Tip
Make sure to memorise all the assumptions for your exams, as it is a common exam question to be asked to recall them.
