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 is one Specified Practical Activities in the 'Periodic table and properties of elements' section:

  • Identification of unknown substances using flame tests and chemical tests for ions and gases

Questions courtesy of Eduqas.

Sample question 1 - Foundation


An experiment involves passing chlorine gas over hot iron wool.

a) Describe how to test for chlorine gas.

In your answer, include the observations you would make if the gas is chlorine. [2 marks]

b) Give the reason why the experiment is carried out in a fume cupboard. [1 marks]

a) Place damp litmus paper in the gas [1]

If the litmus paper is bleached/turns white the gas is chlorine [1]

b) Chlorine is toxic/poisonous [1]

Sample question 2 - Foundation


A teacher adds a few drops of universal indicator solution to a big container of water.

She then adds a small piece of sodium, and a chemical reaction occurs.

The products of the reaction are hydrogen and sodium hydroxide.

Describe and explain the colour change observed in the mixture of universal indicator and water. [2 marks]

Colour change from green to purple [1]

Because water is neutral and sodium hydroxide is alkaline [1]

Sample question 3 - Higher


Compare the tests for hydrogen and oxygen. Include one balanced symbol equation in your answer. [6 marks]

For Oxygen:

  • use a glowing splint to test for oxygen [1]
  • it will relight if oxygen is present [1]

For Hydrogen:

  • use a lighted splint to test for hydrogen [1]
  • it will go out/explode with a squeaky pop if hydrogen is present [1]
  • the equation for the hydrogen test reaction is 2H2 + O2 → 2H2O
  • [1] for correct reactants and products; [1] for correctly balancing numbers

Sample question 4 - Higher


A teacher demonstrates the reaction of potassium with water.

This is what he does:

  1. fill a big glass container with water
  2. place a transparent plastic screen between the container of water and the students
  3. remove a lump of potassium metal from its container
  4. use a knife to cut off a pea-sized piece of potassium
  5. replace the lump of potassium in its container, and fasten the lid
  6. place the pea-sized piece of potassium in the trough of water

a) Suggest a reason for step 2. [1 mark]

b) Suggest a reason for step 5. [1 mark]

c) Describe two observations the students would make in step 6. [2 marks]

a) So that if reacting potassium leaves/jumps off the surface of the water, students will not be injured [1]

b) To avoid the possibility of the bigger lump of potassium reacting with water [1]

c) Two from: quickly melts to form a ball; burns violently with sparks and a lilac flame; reacts rapidly, often with a small explosion [2]