Separating mixtures

Separating mixtures

1. Can be used to separate a solid from a liquid.

   • Only works if the solid cannot dissolve in the liquid.
     • The solid is called the residue and the liquid is called filtrate.
   • Filtration

2. Mixture

   • Contains two or more substances that have not reacted chemically with each other.
     • A mixture can be separated by physical methods

3. Crystallisation

   • separates solids that have dissolved (solids) in a liquid (solvents).
     • this id done by heating the solution so that the liquid evaporates.
       • Crystals are then washed with cold water to wash impurities.

4. Distillation

   • Heating
   • Evaporating
   • Cooling
   • Condensing

5. Fractional Distillation

   • A mixture of multiple liquids can be separated from each other.
   • Can also be used to separate gases mixed together.
   • Only works if the substances mixed together have different boiling points (one temperature at which they turn from a liquid to a gas).
   • Small molecules (low boiling point, very volatile, flows easily and ignites easily).
   • Large molecules (high boiling point, not volatile, doesn't flow easily, doesn't ignite easily).

6. Chromatography

   • Used to separate colours
     • A mix of dyes will be separated out as a solvent (a liquid) rises up.
     • Pencil line so that the ink from the line doesn't rise with the ink being tested.
       • Yellow
         • Red
         • Blue
     • If the same dye is in both samples then there will be an identical spot at the same height above the line