Mixtures And Chromatography

Mixtures And Chromatography

1. Mixtures

   • No chemical bond, separated easily
   • Separated with physical methods e.g. Distillation, chromatography, crystallisation
   • Air is a mixture of manly nitrogen, CO2, argon and oxygen, separated easily
   • Crude oil a mixture of different length hydrocarbon molecules
   • Substance not affected by being part of the mixture

2. Chromatography

   • Used to separate dyes and ink
   • 1) draw line near bottom of filter paper in pencil as it is insoluble
   • 2) add spot of ink and put paper in beaker of solvent e.g. Water
   • 3) solvent depends on what's being tested e.g. Some compounds will dissolve in water but some may need ethanol
   • 4) make sure ink isn't touching solvent
   • 5) place lid on top of container to stop solvent evaporating
   • 6) solvent steps up paper carrying ink with it
   • 7) each dye will form a different spot in the ink and the dyes move up the paper at different rates
   • 8) if any inks are insoluble they stay on the base line
   • 9) when solvent has nearly reached the top remove it and leave it to dry
   • 10) the end result is a pattern of spots called a chromatogram