separation

• Chromatography

  Separate mixture
• Chromatography

  1. Spot mixture on pencil baseline

  2. Solvent below baseline

  3. Solvent carry mixture substance - separate

  4. Diff substance move up paper DIFF rate (stick to paper, or dissolve readily)

  5. Resulting pattern: chromatogram
• Rf value

  Distance travelled by substance (solute) / Distance travelled by solvent (solvent front)
• Locating agent

  Spray chromatogram with locating agent (for colorless chemicals like amino acids)
• Simple distillation


  Separate liquid/solvent from solution
• Simple distillation

  1. Heated (round bottom flask) - boil

  2. Very diff bp: lowest bp -> evaporate

  3. Condenser: vapor cooled, condense, collected in beaker

  4. All water evaporate - solid residue in flask

  
  

  A thermometer is placed to ensure the highest boiling point is not exceeded
• Fractional distillation


  Separate mixture of liquids
• Fractional distillation

  1. Fractionating column top

  2. Mixture heated (in flask)

  3. Different boiling points, evap at diff tmp

  4. Reach lowest bp's tmp - reach top column

  5. Top column cool - substance (high bp) condense and run down flask

  6. Collect first fraction - raise tmp until next subtance reach top

  7. Beaker changed
• Filtration


  Separate insoluble solid from liquid
• Filtration

  1. Filter paper, funnel -> pour

  2. Solid residue -> wash solid (distilled water)

  3. Leave to dry
• Crystallisation


  Separate soluble solid from solution
• Crystallisation

  1. Gently heat solution in evap dish

  2. Water evap -> solution more conc

  3. Point of crystallisation - crystal form

  4. Remove dish from heat, leave solution cool

  5. Salt form more crystal (become insoluble in cold, high conc solution)

  6. Filter crystal out solution

  7. Leave in WARM place - to dry

  8. Can use drying oven, dessicator: chemicals remove water from surrounding