Chemistry S3

• dependant variable of chromatography

  different solubility of components in the same solvent
• dependant variable of fractional distilisation

  different boiling points
• dependant variable of simple distilisation

  different boiling points
• dependant variable of crystallisation

  solubility of solute should increase significantly with decreasing temperature
• dependant variable of evaporation to dryness

  solid must be able to withstand high temperatures, solubility does not change with temperature
• dependant variable of filtration

  particle size
• dependant variable of centrifugation

  solid particles are so small that they spread throughout the liquid and remain in suspension
• dependant variable of decantation

  solid must be able to settle in the solvent (insoluble, high relative density)
• dependant variable of separating funnel

  different densities and immiscibility
• dependant variable of sublimation

  ability to sublime
• dependant variable of magnetic separation

  contains one magnetic substance, ability to be magnetised
• factors affecting diffusion (5)

  temperature, agitation, surface area, concentration gradient, relative molecular mass
• How does kinetic theory explain diffusion

  Dye and water particles move and collide with each other, result in the spreading of the dye particles
• Energy (KE and PE) cooling

  temperature decrease = KE decrease and PE stays the same

  temperature stays the same (change of state) = KE stays the same and PE decrease
• Energy (KE and PE) heating

  temperature increase = KE increase and PE stays the same

  temperature stays the same (change of state) = KE stays the same and PE increase
• How external pressure affects separation between particles and volume of gas

  external pressure increase, separation between gas particles decrease, volume of gas decrease
• Energy when temperature decreases

  Energy is released by the formation of forces of attraction between particles
• Energy when temperature increases

  Energy is absorbed for breaking the forces of attraction between particles
• State change from gas to solid

  deposition
• State change from solid to gas

  sublimation
• Vapour pressure in boiling

  same as atmospheric pressure
• Vapour pressure in evaporation

  less than atmospheric pressure
• Inter-particle forces in a gas

  less than average energy of particles
• Movement of particles in a gas

  move quickly in random directions in a straight line, and sometimes collide with each other
• Arrangement of particles in a gas

  irregular patter, far apart
• Inter-particle forces in a liquid

  comparable to average energy of particles
• Movement of particles in a liquid

  move past each other in random directions
• Arrangement of particles in a liquid

  irregular pattern, somewhat close together
• Inter-particle forces in a solid

  greater than average energy of particles
• Movement of particles in a solid

  vibrate in a fixed position
• Arrangement of particles in a solid

  regular pattern, very close together