Mixtures and chromotography

• What is different about a mixture compared to a compound?

  there is no chemical bond between the different parts of a mixture
• How can mixtures be seperated?

  -Filtration

  -Crystallisation

  -Simple distillation

  -Fractional distillation

  -chromotography
• What is air?

  Air is a mixture of gases,mainly nitorgen,oxygen carbon dioxide and argon.These gases can all be seperated out fairly easily.
• What is crude oil?

  a mixture of different hydrocarbon molecules
• What is a mixture?

  A mixture is a physical combination of two or more substances that aren't chemically joined.
• Paper chromotography

  1)Draw a line near the bottom of a sheet of filter paper(use a pencil(pencil marks are insoluble))

  2)Add a spot of the ink to the line and place the sheet in a beaker of solvent

  3)The solvent used depends on what's being tested.Some compounds dissolve well in water,but sometimes other solvents,like ethanol,are needed

  4)Make sure the ink isn't touching the solvent-you don't want it to dissolve into it

  5)Place a lid on top of the container to stop the solvent evaporating

  6)The solvent seeps up the paper,carrying the ink with it.
• Paper chromotography continued

  7)Each different dye in the ink will move up the paper at a different rate so the dyes will seperate out.Each dye will form a spot in a different place-1 spot per dye in the ink.

  8)If any of the dyes in the ink are insoluble (won't dissolve)in the solvent you've used,they'll stay on the baseline.

  9)When the solvent has nearly reached the top of the paper,take the paper out of the beaker and leave it to dry.

  10)The end result is a pattern of sports called a chromatogram.