Topic 2 - Mixtures, compounds, separation and purification

MIXTURES AND COMPOUNDS

• Physical change:
  • a new substance is NEVER formed
  • temperature does not change much
  • there is no change in mass
  • usually easy to reverse.

• Chemical change:
  • a new substance is ALWAYS formed
  • the temperature oftens changes quite a bit
  • there may be a change in mass
  • usually very difficult to reverse. 

• Some ways of seperating mixtures are filtration, evaporation, distillation and chromatography.

FRACTIONAL DISTILLATION

• Ethanol and water are soluble in one another in any proportion - they are said to be miscible. 
• The vapour that is condensed to form a liquid is called a distillate. 
• The liquid left in the flask will be richer in the other substance. 
• Makers of whisky used to separate out the ethanol from their brew via fractional…