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Boss quiz

10 questions on the whole topic. You get one try at each.

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  1. Which of these is a pure substance?

    • Orange juice
    • Air
    • Sea water
    • Gold

  2. A pure substance melts…

    • over a range of temperatures
    • only when it is stirred
    • at one fixed temperature
    • at any temperature

  3. Sugar dissolves in a cup of tea. What is the sugar?

    • The solvent
    • The solute
    • The solution
    • The residue

  4. 10 g of salt dissolves in 90 g of water. What is the mass of the solution?

    • 100 g
    • 90 g
    • 10 g
    • 80 g

  5. Crystals sit at the bottom of a solution and no more will dissolve. What is the solution?

    • Filtered
    • Pure
    • Saturated
    • Insoluble

  6. What is the solid left in the filter paper called?

    • The filtrate
    • The residue
    • The solute
    • The solvent

  7. Which method gets salt crystals from salt solution?

    • Chromatography
    • Filtration
    • Stirring
    • Evaporation

  8. In distillation, what happens in the condenser?

    • Crystals form
    • A solid dissolves
    • A gas cools and turns back into a liquid
    • A liquid boils

  9. Which method separates the dyes in an ink?

    • Filtration
    • Distillation
    • Chromatography
    • Evaporation

  10. Which method gets pure water from sea water?

    • Distillation
    • Crystallisation
    • Filtration
    • Chromatography
Answers
  1. Gold. Gold is a single element. The other three are mixtures.
  2. at one fixed temperature. A mixture melts over a range. A pure substance has one melting point.
  3. The solute. The solute is the substance that dissolves.
  4. 100 g. Mass is conserved: 10 g + 90 g = 100 g.
  5. Saturated. A saturated solution can dissolve no more solute at that temperature.
  6. The residue. The residue stays in the paper. The filtrate goes through.
  7. Evaporation. The water evaporates and the salt is left behind.
  8. A gas cools and turns back into a liquid. Cold water round the condenser cools the vapour, so it condenses.
  9. Chromatography. The dyes travel different distances up the paper.
  10. Distillation. The water is evaporated, then condensed and collected. The salt stays behind.