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KS3 Chemistry:

Mixtures
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10 minutes maximum! (can you do it in 5?)  

Q1-4. These questions are about sugar water:

water glass  

 1. When sugar dissolves in warm water, the water is called..

  • A. a solute.
  • B. a solvent.
  • C. a dissolvant.
  • D. a dissolute.

2. Sugar dissolves in water easily. This process is..

  • A. a chemical change because atoms have been rearranged in a reaction.
  • B. a physical change because atoms have been rearranged in a reaction.
  • C. a chemical change because NO atoms have been rearranged in a reaction.
  • D. a physical change because NO atoms have been rearranged in a reaction.

3. The sugar can be recovered from the water by..

  • A. filtering the water.
  • B. chromatography.
  • C. evaporating the water.
  • D. diffusion.

4. Which of these sentences best describes if sugar water is a pure or impure substance?

  • A. Pure substance as no other chemicals have been added to the salt water.
  • B. Pure substance as all the molecules are the same.
  • C. Impure substance as there are several different elements in the sugar water.
  • D. Impure substance as there are 2 types of molecules present.

 

5. Some water in a container used for camping is found to have some sand and other dirt particles in it. What is the simplest method to remove these insoluble particles?

  • A. filtering the water.
  • B. chromatography.
  • C. evaporating the water.
  • D. diffusion.
water bottle

 

6-8. Some red food colouring is added to a beaker containing hot water. The red colour slowly spreads throughout the water as shown here:

food colouring in water

 

6. What is the name given to this process?

  • A. Dispersion.
  • B. Diffraction.
  • C. Distillation.
  • D. Diffusion.

7. How does this process happen?

  • A. The particles spread from a small region of low concentration to a larger region of high concentration.
  • B. The particles spread from a small region of high concentration to a larger region of low concentration.
  • C. The particles spread from a large region of high concentration to a smaller region of low concentration.
  • D. The particles spread from a large region of low concentration to a smaller region of high concentration.

8. Complete the following sentence:

 

If the water is cooler, the red colour will spread .

9-10. The image shows some inks separating out as water spreads upwards through some filter paper:

Key:

  • 1 = water
  • 2 = filter paper
  • 3 = black ink dot
  • 4 = coloured ink dots
  • 5 = water 'front' moving upwards
  • 6 = pencil 'start' line
inks spreading through filter paper

9. What is the name given to this process of separating chemicals?

  • A. Filtering.
  • B. Chromatography.
  • C. Distillation.
  • D. Diffusion.

10. Why is pencil used as the bottom line?

  • A. It makes it easier to see.
  • B. The graphite markings from the pencil are not soluble in water.
  • C. The graphite markings from the pencil diffuse easily.
  • D. The graphite markings from the pencil are made of several ink colours.