Mixtures and chromatography

• What are mixtures composed of?

  Mixtures are lots of separate things all mixed together.
• How can mixtures be separated?

  Mixtures can be separated by physical methods such as filtration, crystallisation, distillation, and chromatography.
• What is the main component of air?

  The air is a mixture of gases, mainly nitrogen, oxygen, carbon dioxide, and argon.
• What is gasoline composed of?

  Gasoline is a mixture of different length hydrocarbon molecules.
• How do the properties of a mixture compare to its components?

  The components of a mixture retain their individual properties and do not affect each other.
• What happens when iron powder and sulfur powder are mixed?

  The mixture will show the properties of both iron and sulfur.
• What is the first step in paper chromatography?

  • Draw a line near the bottom of a sheet of filter paper using a pencil.
• Why should a pencil be used to draw the line in chromatography?

  Pencil marks are insoluble and won’t dissolve in the solvent.
• What should you do after adding a spot of ink to the line in chromatography?

  Place the sheet in a beaker of solvent without letting the ink touch the solvent.
• What is the purpose of placing a lid on the container during chromatography?

  The lid stops the solvent from evaporating.
• What happens to the solvent during chromatography?

  The solvent creeps up the paper, carrying the ink with it.
• Why do different dyes in ink separate during chromatography?

  Each dye moves up the paper at a different rate.
• What happens if a dye is insoluble in the solvent used in chromatography?

  The insoluble dye will stay on the baseline.
• What is the final result of a chromatography experiment called?

  The final result is called a chromatogram.
• What are some real-life applications of chromatography?

  • Testing athletes' urine samples for performance-enhancing drugs
  • Testing unknown substances at crime scenes