Practical questions

You will complete 12 required Specified Practical Activities if you are studying GCSE Chemistry, and 27 if you are studying GCSE Combined Science (nine of these are in Chemistry). These help you develop some key practical techniques in Chemistry.

You could be asked questions about the apparatus, methods, safety precautions, results, analysis and evaluation of these experiments.

There are two Specified Practical Activities in the 'Chemistry of acids' section:

  • preparation of crystals of a soluble salt from an insoluble base or carbonate
  • titration of a strong acid against a strong base using an indicator

Questions courtesy of Eduqas.

Sample question 1 - Foundation

Question

One method of preparing dry copper(II) sulfate crystals is by reacting a carbonate with a dilute acid. The information below shows the stages a pupil follows to make copper(II) sulfate crystals.

Three stages of making copper sulfate

a) Name the acid used in the process. [1 mark]

b) Name gas A formed in stage 1. [1 mark]

c) Name the substance removed during stage 3. [1 mark]

a) sulfuric acid [1]

b) carbon dioxide [1]

c) (unreacted) copper(II) carbonate [1]

Sample question 2 - Foundation

Question

The diagrams below show the stages in making the compound zinc sulfate by reacting zinc carbonate with dilute sulfuric acid. The diagram showing the apparatus for stage 2 is missing.

Three stages of making zinc sulfate

a) State what you would see when excess zinc carbonate is added. [2 marks]

b) State why excess zinc carbonate is added. [1 mark]

c) Draw the apparatus you would use to carry out stage 2. Label the excess zinc carbonate on your diagram. [3 marks]

a) solid/zinc carbonate left at bottom of beaker [1] and gas given off [1]

b) to neutralise all the acid [1]

c) a diagram showing a filter funnel [1], with filter paper inside [1], and excess zinc carbonate shown in the filter paper [1]

Excess zinc carbonate through a filter funnel and paper

Sample question 3 - Higher

Question

A student has three acidic solutions, listed below:

  • 0.1 mol/dm3 ethanoic acid
  • 0.1 mol/dm3 hydrochloric acid
  • 1.0 mol/dm3 hydrochloric acid

The solutions are in unlabelled bottles.

Describe how the student could use universal indicator paper to find out which acid is which.

In your answer, state the apparatus needed, and how to use the results to identify the acids. [5 marks]

Place three test tubes in a test tube rack. [1]

Label each bottle, and pour approximately 1 cm3 of solution from each bottle into a labelled test tube. [1]

Dip a separate piece of universal indicator paper into each test tube. [1]

Compare the colours of the indicator paper to the colours shown on the packet, and deduce the pH of each solution. [1]

The solution with the highest pH is 0.1 mol/dm3 ethanoic acid, and the solution with the lowest pH is 1.0 mol/dm3 hydrochloric acid. [1]

Sample question 4 - Higher

Question

Elliot makes zinc chloride crystals from zinc oxide and an acid.

This is what he does:

  1. Add zinc oxide to dilute acid until some zinc oxide remains unreacted.
  2. Filter the mixture.
  3. Pour the filtrate into an evaporating basin.
  4. Heat the filtrate over a water bath until crystals appear around the edge.
  5. Remove the heat and leave in a warm, dry place for a few days.

a) Name the acid used in step 1. [1 marks]

b) Describe and explain one improvement to step 1. [1 marks]

c) Explain why Elliot filters the mixture in step 2. [1 marks]

d) Write a balanced chemical equation for the reaction, including state symbols.

Use these formulae: ZnO, ZnSO4, HCl, H2O [4 marks]

a) Hydrochloric acid [1]

b) Heat [1] to increase the amount of zinc oxide that reacts/to increase the rate of the reaction [1]

c) To remove unreacted zinc oxide [1]

d) ZnO(s) + 2HCl(aq) → ZnSO4(aq) + H2O(l) [4]

If equation not completely correct, award [1] for correct reactants and products; [1] for correct state symbols; [1] for a properly balanced equation