Kinetic Particle Theory

• Solid:

  • Strong intermolecular forces
  • Fixed lattice arrangement
  • Particles vibrate in fixed position; fixed shape and volume
• Liquid:

  • Weaker intermolecular forces than solids
  • No fixed arrangement; particles can move and slide over each other
  • Particles slide; fixed volume
• Gas:

  • Almost no intermolecular forces
  • Particles far apart and move quickly
  • Random movement; no fixed shape or volume
• When a solid is heated, the particles gain sufficient energy to overcome the strong intermolecular forces.
• When a solid is heated particles eventually can slide over each other in a more random motion- solid expands until the structure is broken at melting point.
• When a liquid is heated to its b.p, the particles overcome the relatively weaker intermolecular force to escape the liquids surface and move around in continuous rapid motion – the liquid has boiled
• In the vapor, the particles move in rapid random motion. This movement is due to the collision of vapor particles with air particles.
• When gaseous particles are heated in a closed environment, the increase in kinetic energy causes increased collisions with other particles as well as the walls of the container- pressure increases.