P3

• Particle Model of Matter

  Solids, Liquids & Gases
• States


  • Solid
  • Liquid
  • Gas
• Solid


  • Arrangement: Regular
  • Movement: Vibrate about a fixed position
  • Closeness: Very close
• Liquid


  • Arrangement: Random
  • Movement: Flow around eachother
  • Closeness: Close
• Gas


  • Arrangement: Random
  • Movement: Move quickly in random directions
  • Closeness: Far apart
• Changes of State


  1. Materials change states due to a change in their internal energy

  2. When heated, kinetic energy of particles increases and intermolecular bonds break

  3. When cooled, kinetic energy of particles decreases and intermolecular bonds form
• Latent Heat


  • Energy transferred to a substance when it changes state
  • Latent Heat of Fusion: solid to liquid/liquid to solid
  • Latent Heat of Vaporisation: liquid to gas/gas to liquid
• Internal Energy


  Sum of particles' kinetic energy and potential energy
• Heat


  Total energy of an object due to kinetic energy of particles, measured in Joules
• Temperature


  Measures average kinetic energy of molecules, measured in Celsius or Kelvin
• Specific Latent Heat of Fusion

  Energy required to change 1 kg of material from solid to liquid at constant temperature
• Specific Latent Heat of Vaporisation

  Energy required to change 1 kg of material from liquid to gas at constant temperature
• Calculating Specific Latent Heat

  E = m x L
• Particle Motion in Gases

  • Pressure results from collisions between gas particles and container walls
  • As temperature increases, particles gain kinetic energy and move faster, increasing collisions and expanding the container
• Density


  • Amount of mass in a volume, indicating how tightly particles are packed
  • Calculated as ρ = m/V
• Specific Heat Capacity


  • Energy required to raise temperature of 1 kg substance by 1 °C
  • Calculated as ΔE = m x c x Δθ