States of Matter and Separation - Kinetic Theory of Matter

The Kinetic Theory of Matter states that all matter is composed of small particles (atoms, molecules, or ions) that are in constant, random motion.

In a solid, particles are closely packed in a regular lattice, vibrating about fixed positions with low kinetic energy. The attractive forces are strong, resulting in a fixed shape and volume.

In a liquid, particles are close together but arranged randomly. They have enough energy to slide past one another, meaning liquids have a fixed volume but take the shape of their container.

In a gas, particles are far apart and move rapidly in all directions. They have high kinetic energy and negligible intermolecular forces, leading to no fixed shape or volume. Pressure is caused by particles colliding with the walls of a container.

Temperature is a measure of the average kinetic energy ($KE$) of the particles. As temperature increases, particle speed increases, as shown by the relation $KE = \frac{1}{2}mv^2$.

Phase changes occur at constant temperature. During melting or boiling, energy is used to overcome intermolecular forces rather than increasing the speed of particles (Latent Heat).

Diffusion is the net movement of particles from a region of higher concentration to a region of lower concentration. The rate of diffusion is inversely proportional to the square root of the molecular mass: $Rate \propto \frac{1}{\sqrt{M}}$.

Separation techniques utilize physical properties: Filtration (solubility/size), Distillation (boiling point), and Chromatography (solubility/adsorption).