States of Matter and Separation - Changes of State and Diffusion

The Kinetic Particle Theory states that all matter is composed of tiny particles that are in constant, random motion. The average kinetic energy of these particles is represented by $E_{k} \propto T$, where $T$ is the absolute temperature in Kelvin.

Solids have particles packed closely in a regular lattice, vibrating about fixed positions. Liquids have particles that are close together but can slide over one another. Gases have particles that are far apart and move rapidly in all directions.

Phase changes occur when energy is added or removed. Processes requiring energy (endothermic) include melting ($solid \rightarrow liquid$), evaporation/boiling ($liquid \rightarrow gas$), and sublimation ($solid \rightarrow gas$).

Processes releasing energy (exothermic) include freezing ($liquid \rightarrow solid$), condensation ($gas \rightarrow liquid$), and deposition ($gas \rightarrow solid$).

Diffusion is the net movement of particles from a region of higher concentration to a region of lower concentration, driven by the random motion of particles.

The rate of diffusion is influenced by temperature and molecular mass. According to the kinetic theory, at the same temperature, particles with a lower relative molecular mass ($M_{r}$) travel at higher average speeds than heavier particles.