Distillation

• what are the 2 types of distillation

  simple distillation and fractional distillation
• What is simple distillation used to separate


  Liquids from Solutions
• What is fractional distillation used to separate


  Mixture of liquids with similar boiling points
• How to carry out simple distillation


  1. solution is heated and part of solution with the lowest boiling point evaporates first
  2. the vapour is cooled and condensed (turned back into liquid) and collected
  3. rest of solution is left behind in flask
• What can you use simple distillation for


  To get pure water from seawater
• Problem with simple distillation


  Can only separate things with very different boiling points
• How to carry out fractional distillation

  1. put mixture in a flask, put fractionating column on top and heat
  2. different liquids have different boiling points so they will evaporate at different temperatures
  3. liquid with lowest boiling point evaporates first and will reach the top of the column
  4. liquids with higher boiling points may start to evaporate but the column is cooler towards the top so they condense and run back down the flask
  5. once first liquid is collected, raise the temperature until the next one reaches the top