Kinetic Particle Theory
- All matter is made of many small particles that are constantly moving.
- The properties of solid, liquid and gas can be explained by the movement and arrangement of the particles.
Properties of State
Solid
- Have a fixed shape and maintain the shape
- Difficult to compress
Liquid
- Do not have a fixed shape and fill the bottom of the container
- Difficult to compress
Gas
- Do not have a fixed shape and expand to fill any container
- Easy to compress
Brownian Motion
- Liquid and gas particles move randomly.
- This is due to the constant bombardment from surrounding particles.
Effect of Temperature on Thermal Expansion
When a matter is heated, heat causes the particles to move faster (thermal energy is converted into kinetic energy).
Solid
- Particles vibrate faster about their fixed point.
- The volume increase of solid when heated is very small.
Liquid
- Particles move around faster.
- Liquid expands more than solids because the attractive bond between the particles is smaller than in solids.
Gas
- Particles move around with faster speed.
- Since particles within gas are further apart and weakly bonded to each other, gas expands a lot when heated.
- When gas is contained in a fixed volume container, the particles collide on the walls of the container more frequently and with a bigger force when it is heated. Therefore, the pressure that gas exerts on the walls of the container increases.