mixtures and chromatography

• What is a mixture?

  A combination of two or more substances that are not chemically bonded.
• Can mixtures be easily separated?

  Yes mixtures can be easily separated.
• What parts of a mixture can there be?

  elements or compounds.
• How can parts of a mixture be separated?

  Through physical methods such as, filtration, crystallisation, simple distillation, fractional distillation and chromatography.
• What is the first step in paper chromatography?

  Draw a line near the bottom of filter paper
• Why should pencil marks be used in paper chromatography?

  Pencil marks are insoluble and won't dissolve
• What should be done after adding a spot of ink to the line?

  Place the sheet in a beaker of solvent
• Why must the ink not touch the solvent in paper chromatography?

  To prevent dissolving the ink early.
• What should be done to prevent solvent evaporation during chromatography?

  Place a lid on top of the container
• What happens to the solvent during paper chromatography?

  The solvent seeps up the paper carrying the ink
• How do different dyes behave in paper chromatography?

  They move at different rates and separate out
• What happens to insoluble dyes in paper chromatography?

  They stay on the baseline
• What should you do when the solvent nearly reaches the top of the paper?

  Take the paper out and leave it to dry
• What is the final result of the paper chromatography process called?

  A pattern of spots called chromatography
• The properties of a mixture are just a mixture of the properties of the separate parts
• Air is a mixture of gases, mainly nitrogen, oxygen, carbon dioxide and argon
• How is paper chromatography carried out?

  1. Draw line near bottom of filter paper
  2. add spot of ink and place in beaker of solvent
  3. place lid on top of container to stop solvent evap
  4. solvent seep up paper carrying ink with it
  5. when solvent reaches top of paper take paper out of beaker and leave to dry
• What is an example of chromatography?

  Separating different dyes in an ink