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C2 (Filtration and crystallization, Paper chromatography, Assessing purity…

- - - - Physical properties such as boiling point between substances being seperated
  - - - Suitable solvent must be chosen to ensure desired substance only dissolves in it and not other substance or impurities
  - - - Filter paper will only allow small liquid particles to pas through in filtrate
        
        Solid particles too large to pass through filter paper so will stay behind as residue
  - - - Test if solution is saturated by dipping clean, dry, cold glass rod into the solution
        
        If solution is saturated, crystals form on glass rod when it is removed and allowed to cool
        
        Then they are washed into distilled water to remove impurities and allowed to dry
  - - - E.g. pure liquid from mixture of liquids
    - - Solution is heated and pure water evaporates
        
        Producing vapor which rises through neck of round-bottomed flask
      - Vapour passed through condenser, where it cools and condenses, turning into pure water collected by the beaker
    - - Separate two or more liquids that are miscible with one another
        
        E.g. Ethanol and water from mixture
      - Method
        
        Solution is heated to temperature of substance with lowest b.p
        
        Will rise and evaporate first
        
        vapors pass through condenser where they cool and condense, turning into liquid that will be collected in a beaker
        
        All substance evaporated collected and leaving behind other components of mixture
- - - - Pencil is used as ink would run into chromatogram along with samples
    - - Substance with higher solubilities travel further than others,
  - - - (Help match unknown spot or set of spot in order to identify it)
    - - pure substance show only one
- - - - E.g. Water has a bp of 100°C and a mp of 0°C
  - - - Melt or boil at different temps
  - - - Bp are commonly determined by distillation
      - E.g. Mp analysis routinely used to asses purity of drugs
        
        This is then compared to data tables
        
        Closer measured value to actual melting / boiling point, the purer the sample is
        
        If sample contains impurities
        
        Bp may appear higher than sample's actual mp
        
        Mp may appear lower than sample's actual mp
- - - - Making sample runs visible to the naked eye
  - - - Can be compared with Rf values of known substances under same conditions
    - - Rf = Distance travelled by substance / distance travelled by solvent