Kinetic+Theory

· Much of the physical behaviour of gases can be explained using the kinetic theory. · Different gases unlike different solids and liquids behave in a similar manner. · Laws and relationships have been developed and they can be applied to all gases regardless of their chemical composition. · These are based on the idea of an “ideal gas”. This is a gas that obeys these laws perfectly. · In reality and practice no gas behaves ideally however under normal conditions the behaviour of most gases is close enough to being ideal and thus these laws and relationships can be used. · Kinetic theory is based on a model of an ideal gas that assumes that: “**All gases** are made up of **particles** of     matter in a state of **constant motion.**” · The term kinetic indicates that it is the motion of these particles that affects their physical properties. **__________________________________________________________________________**   **Things to know:** 1. Gases consist of tiny particles called molecules, (noble gases consist of atoms). 2. Average distance between the molecules of a gas is very large in comparison to the size of each gas molecule. 3. The molecules of a gas move in rapid, random, straight –line motion resulting in collisions with each other and with the sides of the container. 4. The molecules of a gas exert minor attractive or repulsive forces on one another. 5. All collisions of gas molecules are perfectly elastic: there is no net energy loss during these collisions. 6. The average kinetic energy of the molecule increases as the temperature of the gas increases.
 * The Kinetic Theory of Gases**

relationship between:

heat and temperature

change of phase

vapour pressure and factors that affect vapour pressure

effect on gases of changes in pressure, temperature and volume

characteristics of gases

boiling point of a liquid