separating mixtures

• Chromatography is used to separate pigments of ink and dye.
• Filtration is when water passes through a filter  and leaves remaining particles behind
• Evaporation is used to separate soluble solids from liquids.
• Chromatography


  • Method used to separate a mixture of different colours (inks/dyes) or chemicals based on their solubility in a solvent
• Chromatography method


  1. Draw a line in pencil approximately 2cm from the bottom of your chromatography paper

  2. Draw a cross, in pencil on the line to mark the start point of the colour (repeat for as many colours as you want to test)

  3. Draw a dot on top of the cross in the test sample of your choice (repeat for the different samples)

  4. Place the bottom of the paper into a beaker with a small amount of water. Ensuring that the water does not go above the pencil line

  5. Leave the paper in the beaker to allow the water to travel up the paper

  6. When the water reaches the top of the paper remove from the beaker and carefully add a pencil line to show where the water has travelled to this is the Solvent Front (the distance traveled by the solvent)

  7. Work out R, values for each of the colours you have used (R, distance travelled by solute/distance travelled by solvent)
• Pencil is used as it is NOT water-soluble so doesn't affect the results
• Paper dip attached to solvent front
• chromatography happens because

  • the more solutes dye travels further up the paper
  • dyes travel at different speeds
  • dyes travel different distances
  • dyes have different Rf values