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Year 11 Science — Chemical reactions and equations

Balance a skeletal equation by counting atoms, name the five kinds of reaction the chapter sets out, and say which substance has been oxidised and which reduced.

Name: ________________________

  1. 1.Sort each reaction by the kind of reaction it is.

    Groups: Combination · Decomposition · Displacement · Double displacement

    • Carbon burning in oxygen to give carbon dioxide
    • Calcium oxide and water make slaked lime
    • Sodium sulphate solution mixed with barium chloride solution
    • An iron nail left in copper sulphate solution
    • Ferrous sulphate crystals heated in a boiling tube
    • Limestone heated in a kiln

  2. 2.Zinc granules are dropped into dilute sulphuric acid. Bubbles rise round them and the tube grows warm. Which two of the chapter's signs of a reaction is that?

    • a) The colour changes, and a gas is given off
    • b) The state changes, and the colour changes
    • c) The temperature changes, and the colour changes
    • d) A gas is given off, and the temperature changes

  3. 3.Butter kept too long smells and tastes different, because the fat in it has been oxidised. What is this change called? Answer with one word.

  4. 4.An equation is drawn out below. Tap the side the products are written on.

    Write the number of the part.

    12

  5. 5.Sodium reacts with water: __ Na + 2H₂O → 2NaOH + H₂. Which coefficient belongs in the gap?

    • a) 3
    • b) 1
    • c) 4
    • d) 2

  6. 6.Bags of crisps are flushed with nitrogen before they are sealed. What is that for?

    • a) It stops the bag from being crushed
    • b) It cools the crisps down
    • c) It keeps the fat in them from being oxidised
    • d) It keeps the crisps dry

  7. 7.Limestone is heated strongly in a kiln and gives quick lime and carbon dioxide. What kind of reaction is that?

    • a) A displacement reaction
    • b) A precipitation reaction
    • c) Thermal decomposition
    • d) A combination reaction

  8. 8.Iron nails are left in blue copper sulphate solution for twenty minutes. What do you see when they come out?

    • a) The nails have dissolved and the solution is green
    • b) The nails are unchanged and the blue is deeper
    • c) The nails have turned black and the solution is clear
    • d) The nails have turned brownish and the blue has faded

Answer key — Year 11 Science — Chemical reactions and equations

  1. 1. Calcium oxide and water make slaked lime → Combination; Carbon burning in oxygen to give carbon dioxide → Combination; Ferrous sulphate crystals heated in a boiling tube → Decomposition; Limestone heated in a kiln → Decomposition; An iron nail left in copper sulphate solution → Displacement; Sodium sulphate solution mixed with barium chloride solution → Double displacement
  2. 2. d) A gas is given off, and the temperature changes
  3. 3. rancidity
  4. 4. 2 — The product side
  5. 5. d) 2
  6. 6. c) It keeps the fat in them from being oxidised
  7. 7. c) Thermal decomposition
  8. 8. d) The nails have turned brownish and the blue has faded