Separation and Purification

Separation and Purification

1. Pure substance: Made up of 1 element or compound

   • Pure: Have exact melting and boiling points
   • Impurities cause boiling points to increase

2. Mixture: Made up of 2 or more substances not chemically combined

3. SEPARATE SOLID FROM LIQUIDS

   • Filtration
     • Filter with filter paper then collect residue
   • Evaporation to dryness
     • Heat evaporating dish with bunsen burner until no more water
   • Crystallization
     • Heat solution until saturated then cool to rtp to crystallize solid

4. SEPARATE SOLIDS

   • Use suitable solvent
     • Use a solvent which only 1 solid is soluble in
   • Sublimation
     • Only can perform on iodine, napthalene
   • Using a magnet
     • Use magnet to separate metal from non-metal

5. SEPARATE LIQUIDS FROM A SOLUTION

   • Simple distillation
     • Heat distillation flask with bunsen burner. Separates pure substance from solution

6. SEPARATE LIQUIDS

   • Fractional distillation
     • Separate mixture of miscible liquids with different boiling points
   • Using a separating funnel
     • Separate liquids that do not mix with separating funnel

7. SEPARATING DYES

   • Paper chromatography
     • Separate substance with different solubility in a solvent
     • Rf value = dist travelled by substance / dist travelled by solvent
     • Use locating agent if substance is colourless