States of Matter

• States of matter


  Solid, liquid, gas
• Particle model of matter

  • Particles represented by small solid spheres
  • Gas: particles have the most energy, most spread apart, random arrangement
  • Liquid: particles have more energy than solid, closer together but random arrangement
  • Solid: particles have least energy, not moving/just vibrating, regularly and closely arranged
• Interconversions between states of matter

  1. Melting: solid → liquid

  2. Freezing: liquid → solid

  3. Boiling: liquid → gas

  4. Condensing: gas → liquid
• Melting point


  Temperature at which solid changes to liquid
• Boiling point


  Temperature at which liquid changes to gas
• Changing from solid to liquid to gas

  Particles gain more kinetic energy, move around more, become more randomly arranged and further apart
• Changing from gas to liquid to solid

  Particles lose kinetic energy, move less, become more regularly arranged and closer together
• Diffusion


  Movement of particles from an area of high concentration to an area of low concentration
• Diffusion does not occur in solids as the particles cannot move from place to place (only vibrate)
• Diluting coloured solutions


  Particles of the colour diffuse to the air of low concentration, mixing with the water molecules, causing dilution to occur
• Solvent


  Liquid in which a solute dissolves
• Solute


  Substance that dissolves in a liquid to form a solution
• Solution


  Mixture formed when a solute has dissolved in a solvent
• Saturated solution


  Solution in which no more solute can be dissolved
• Solubility


  Grams of a solute that will dissolve in 100 g of water
• Solubility curves


  • Solubility of solids increases when temperature increases
  • Solubility of gases increases when pressure increases
  • Mass below the line is unsaturated
  • Mass above the line is supersaturated and unstable
• Practical: investigate the solubility of a solid in water at a specific temperature