Separation of Mixtures

Separation of Mixtures

1. SOLID FROM SOLID

   • PHYSICAL
     • MAGNETIC SEPARATION
       • e.g. separate iron from sulfur using magnet
   • CHEMICAL
     • SUBLIMATION
       • Solid sublime to gas
         • Gas rises, collected over cool surface of inverted funnel
     • ADDING A SUITABLE SOLVENT
       • One soluble, one insoluble
       • Filter off mixture, filtrate collected; evaporate off solvent to obtain solute OR crystallisation process

2. LIQUID FROM AQUEOUS

   • SIMPLE DISTILLATION
     • Separates pure solvent (liquid) from solution
       • Boiling point of solvent can be found out bc pure solvent has fixed/exact b.p/m.p

3. SOLID FROM LIQUID

   • INSOLUBLE
     • FILTRATION
       • Residue = solid
       • Filtrate = liquid
   • SOLUBLE
     • EVAPORATING TO DRYNESS
       • Obtain soluble solid from solution by heating until liquid boils off
         • mixture left behind may be impure
     • CRYSTALLISATION
       • pure solid from saturated solution
       • 1. Dissolve impure solid in solvent e.g. water 2. Filter out insoluble impurities
       • 3. Collect filtrate 4. Heat filtrate over evaporating dish; evaporating off water
       • 5. Collect saturated solution (dip glass rod, remove, if crystals form, solution is saturated
       • 6. Leave saturated solution to cool & crystallise then filter to collect crystals

4. LIQUID FROM LIQUID

   • MISCIBLE
     • FRACTIONAL DISTILLATION
       • Separates 2 miscible liquids w different boiling points
         • Liquid w lowest b.p. distills over first
         • Vapours of liquids w higher b.p. condense along fractionating column & fall back into round-bottomed flask
       • Difference w simple distillation: fractionating column
         • glass beads: bigger surface area for vapour to condense off
   • IMMISCIBLE
     • SEPARATING FUNNEL
       • Separates 2 immiscible liquids e.g. water & oil