Chemistry - Separating Mixtures

Chemistry - Separating Mixtures

1. Filtration

   • Used if the product is an insoluble solid that needs to be separated from a liquid reaction mixture
   • It can be used in purification as well
     • Solid impurities in the reaction mixture can be separated

2. Crystallization

   • Method
     • Pour the solution into an evaporating dish
       • Gently heat
         • Once some of the solvents has evaporated, remove the dish and leave to cool
           • The salt should start to form crystals as it becomes insoluble
             • Filter the crystals out of the solution and leave them to dry

3. Simple Distillation

   • Used for separating out a liquid from a solution
   • Method
     • The solution is heated. The part of the solution with the lowest boiling point is evaporated first
       • The vapour is then cooled, condenses and is collected
         • The rest of the solution is left behind
   • You can only separate solutions with different boiling points

4. Fractional Distillation

5. Chromatography

   • Can be used to separate differents dyes
   • Method
     • Draw a line near the bottom of the sheet
       • Add a spot of the ink to the line and place the sheet in a beaker of solvent
         • Make sure the ink isn't touching the solvent
           • Place a lid on the container
             • The solvent will seep up the paper
               • Each different dye will move up the paper at different speeds
                 • When the solvent has nearly reached the top of the paper, take the paper out.
                   • The end result is called a chromatogram