Mixtures

• What are mixtures in chemistry compared to in baking?


  They are lots of separate things all mixed together.
• How do mixtures differ from compounds?

  Mixtures do not have chemical bonds between their parts.
• What types of substances can be found in a mixture?


  Elements or compounds.
• Which physical methods can be used to separate the parts of a mixture?

  Filtration, crystallisation, simple distillation, fractional distillation, and chromatography.
• What is air primarily composed of?

  Nitrogen, oxygen, carbon dioxide, and argon.
• Why can the gases in air be separated easily?


  Because they are part of a mixture.
• What is crude oil a mixture of?


  Different length hydrocarbon molecules.
• How do the properties of a mixture relate to its components?


  The properties of a mixture are just a combination of the properties of its separate parts.
• What happens to the chemical properties of a substance in a mixture?


  They are not affected by being part of a mixture.
• What is an example of a mixture mentioned in the material?

  A mixture of iron powder and sulfur.
• What is the process of paper chromatography?


  1. Draw a line near the bottom of filter paper with pencil.
  2. Add a spot of ink to the line.
  3. Place the paper in a beaker of solvent.
  4. Ensure the ink does not touch the solvent.
  5. Cover the container to prevent evaporation.
  6. The solvent moves up the paper, carrying the ink.
  7. Different dyes move at different rates, forming spots.
  8. Insoluble dyes remain on the baseline.
  9. Remove the paper when the solvent nears the top.

  10. The result is a chromatogram.
• Why should you use a pencil to draw a line on the filter paper for chromatography?


  Pencil marks are insoluble and won't dissolve in the solvent.
• What are some real-life applications of chromatography?


  • Testing athletes' urine samples for performance-enhancing drugs.
  • Analyzing unknown substances at crime scenes.
• What is the end result of a chromatography process called?


  A chromatogram.
• How does chromatography separate different substances in a mixture?


  By allowing each dye to move at different rates up the paper.
• What should be done if any dyes in the ink are insoluble in the solvent used?


  They will stay on the baseline.
• What does a chemical formula represent in a compound?


  The proportion of atoms of each element in a compound
• What does the chemical equation show in a reaction?


  The overall change in a reaction
• What is the word equation for the combustion of methane?

  Methane + oxygen → carbon dioxide + water
• What is the symbol equation for the combustion of methane?

  CH₄ + 2O₂ → CO₂ + 2H₂O
• Why must a chemical equation be balanced?


  To ensure the same number of each atom on both sides
• What do the large numbers in front of formulas in a chemical equation indicate?


  How many units of that element or compound there are
• What defines a mixture in chemistry?


  • Substances made up of different elements or compounds
  • Not chemically bonded to each other
  • Example: air is a mixture
• What is the effect of being part of a mixture on the chemical properties of a substance?


  The chemical properties of a substance aren't affected
• What is the process of paper chromatography used for?


  • To separate components of a mixture
  • Involves a solvent moving up filter paper
  • Components separate based on solubility
• What happens to insoluble components during paper chromatography?


  They stay on the baseline
• What is the role of the solvent in paper chromatography?


  To carry the components up the paper
• What is the first step in the paper chromatography process?


  Applying a spot of the mixture on the pencil line
• What is a chromatogram?


  The result of the separation of components on the paper
• What are the key components involved in paper chromatography?


  • Filter paper
  • Spot of mixture (e.g., ink)
  • Solvent
  • Pencil line