Chemistry: Matter, Mixtures, and Separation - Changes of State and Interconversion of Matter

Kinetic Molecular Theory: Matter is composed of tiny particles that are in constant motion. The kinetic energy ($E_k$) of these particles is directly proportional to the absolute temperature ($T$) of the substance.

States of Matter: Solids have a fixed shape and volume with particles vibrating in fixed positions. Liquids have a fixed volume but take the shape of their container. Gases have no fixed shape or volume and expand to fill any space, where particle distance is much greater than particle size.

Interconversion of Matter: The process of changing from one state to another involves energy transfer. Melting (Solid to Liquid), Boiling (Liquid to Gas), and Sublimation (Solid to Gas) are endothermic processes, meaning they absorb energy ($+\Delta Q$).

Exothermic Processes: Freezing (Liquid to Solid), Condensation (Gas to Liquid), and Deposition (Gas to Solid) release energy ($-\Delta Q$) to the surroundings.

Heating Curves: When a substance is heated, the temperature increases until it reaches a phase change point (Melting or Boiling point). During the phase change, the temperature remains constant because the energy is used to overcome intermolecular forces of attraction rather than increasing kinetic energy.

Evaporation vs. Boiling: Evaporation occurs only at the surface of a liquid and at any temperature, whereas boiling occurs throughout the liquid at a specific boiling point ($T_b$).