Kinetic Particle Theory

• Kinetic Particle Theory


  • the kinetic Particle Theory states that all matter is made up of tiny particles which move randomly all the time
  • matter can exist in the physical states of solid, liquid and gas
• Solid


  • particles are very close together and arranged in an orderly manner
  • very strong forces of attraction
  • particles vibrate in fixed positions
  • particles have very low kinetic energy
  • definite shape
  • definite volume
  • cannot be compressed

  
• Liquid


  • Particles are closely packed and arranged in disorderly manner
  • Forces of attraction between particles are less strong than the forces of attraction between particles in solid, but stronger than forces of attraction between particles in gas
  • particles in liquid slide past one another
  • particles have low kinetic energy but higher than that of particles in solids
  • indefinite shape
  • definite volume
  • cannot be compressed
• Gas


  • particles in gas are very far apart and arranged in a disorderly manner
  • forces of attraction between particles are very weak
  • particles move quickly and randomly in any direction
  • particles have high kinetic energy
  • indefinite shape
  • indefinite volume
  • can be compressed
• FOA

  Forces of attraction between particles in a substance depends on the distance between the particles
• Kinetic Energy of Particles


  • Average kinetic energy of particles in a substance depends on temperature
• Compression


  • Whether a substance can be compressed or not depends on the arrangement of particles (how far apart or closely packed)
• Change in state of Pure substances

  • a pure substance boils and condenses at the same temperature
  • a pure substance melts and freezes at the same temperature
• Evaporation


  • evaporation occurs when some particles at the surface of a liquid have enough energy to overcome the attractive forces between the particles and escape into the air as a gas
  • occurs at any temperature
  • temperature of the substance decreases
  • liquids that evaporate easily are said to be volatile, they usually have low boiling points
• Sublimation


  • sublimation is the process in which a substance in the solid state changes into the gaseous state directly without going through the liquid state
  • takes place when the particles at the surface of the solid possess sufficient energy to break away from the solid and escape as gas
  • vapour deposition is the opposite of sublimation