Concise Summary of Particulate Nature of Matter

  • Particulate Nature of Matter

    • All matter consists of tiny, discrete particles in constant random motion.

    • Particle motion and arrangement vary across different states of matter: solid, liquid, and gas.

  • States of Matter

    • Solid:

    • Shape: Fixed

    • Volume: Fixed

    • Particles: Closely packed, strong attraction, low kinetic energy, vibrate in fixed positions.

    • Liquid:

    • Shape: Not fixed

    • Volume: Fixed

    • Particles: Closely packed but disorderly, moderate attraction, more kinetic energy than solids, can slide over each other.

    • Gas:

    • Shape: Not fixed

    • Volume: Not fixed

    • Particles: Very far apart, weak attraction, high kinetic energy, move randomly at high speeds.

  • Melting and Freezing

    • Melting: Solid to liquid at melting point. Particles gain energy and break free from fixed positions, slide over each other.

    • Freezing: Liquid to solid at freezing point. Particles lose energy, slow down, and settle into fixed positions.

  • Boiling and Condensation

    • Boiling: Liquid to gas at boiling point. Particles gain energy, temperature remains constant during boiling until all liquid vaporizes.

    • Condensation: Gas to liquid, particles lose energy and move closer together.

  • Diffusion

    • Definition: Net movement of particles from high to low concentration.

    • Examples: Smell of perfume spreading, mixing food smells.

    • Influenced by temperature (higher temp = faster diffusion) and particle mass (lighter particles diffuse faster).

  • Expansion and Contraction

    • Heating a solid increases particle energy, causing expansion.

    • Cooling decreases particle energy, causing contraction.

    • Conservation of mass occurs as the number of particles remains constant during these processes.

  • Key Equations and Concepts

    • Changes of state: Solid ↔ Liquid ↔ Gas

    • Melting Point & Freezing Point are phase transition temperatures.

    • Evaporation: Liquid to gas below boiling point; Boiling: occurs at boiling point.

  • Practical Implications of Particle Motion

    • Use of sublimation in dry ice for food transport (solid to gas without becoming liquid).

    • Gaps in railway tracks for thermal expansion to prevent derailments.