Kinetic Theory of Matter

 - The kinetic theory of matter explains the behavior and movement of particles in different states of matter.  

- Matter is anything that has mass and occupies space.  

- Matter is made up of tiny particles such as atoms, molecules, and ions.  

States of Matter  

There are four states of matter: Solids, Liquids, Gases, and Plasma.  

The differences in their properties depend on:  

- Kinetic energy of particles 

- Force of attraction between particles  

Solids  

- Fixed shape, cannot flow.  

- Particles are closely packed and cannot move freely.  

- Cannot be compressed, as particles have no space to move into.  

Liquids  

- Flow and take the shape of their container.  

- Particles move around each other but remain close together.  

- Cannot be compressed, as particles have little free space.  

Gases  

- Flow and completely fill their container.  

- Particles move quickly in all directions.  

- Can be compressed, as particles are far apart with space to move into.  

Phase Changes  

Melting  

- When heat is applied to a solid, the binding forces loosen and the crystalline structure collapses.  

- The temperature at which this occurs is the melting point.  

- Impurities lower the melting point and freezing point.  

Evaporation  

- Occurs when liquid particles at the air‑liquid interface escape into the atmosphere.  

- Happens at all temperatures, but the rate increases with temperature.  

- Depends on the nature of the liquid: covalent liquids evaporate more readily than electrovalent liquids.  

Vapor Pressure  

- In a closed system, evaporated particles collide with each other and the container walls, exerting pressure.  

- At saturation, the rate of evaporation equals the rate of condensation → saturated vapor pressure (SVP).  

- Depends on temperature and nature of the liquid.  

Boiling  

- As a liquid is heated, evaporation increases and SVP rises.  

- When SVP = atmospheric pressure, bubbles form and the liquid boils.  

- The temperature at this point is the boiling point.  

Factors Affecting Boiling Point:  

- Impurities: Increase boiling point.  

- Atmospheric pressure:  

  - Higher pressure → higher boiling point.  

  - Lower pressure → lower boiling point.