AQA GCSE Chemistry (8462), Higher tier · Energy changes › Chemical cells and fuel cells
Practise Cells and batteries. 12 exam-style questions on this subtopic, at up to four difficulty levels, with full mark schemes and a progress tracker. Free, no account needed.
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A battery for a torch is made from four identical cells connected in series, each with a voltage of 1.5 V. Calculate the total voltage of the battery.
6.0 V
Sample questions
Written for this site in the style of AQA exam questions. They are not taken from real past papers.
Question 1Easy5 marks
Cells contain chemicals that react to produce electricity.
(a) Which two things are needed to make a simple cell? Tick (✓) two boxes.[2]
Two different metals
Two pieces of the same metal
An electrolyte
A catalyst
A thermometer
(b) A battery is made from two or more cells. How are the cells connected to produce a greater voltage?[1]
(c) A torch battery contains four cells. Each cell has a voltage of 1.5 V. Calculate the voltage of the battery.[1]
(d) Alkaline batteries are non-rechargeable. Why does an alkaline battery eventually stop working?[1]
Show the answer and mark scheme
(a)Answer: Two different metals; An electrolyte
(b)Answer: In series
in series
(c)Answer: 6.0 V
6(.0) (V)
(d)Answer: One of the reactants is used up, so the chemical reactions stop.
one of the reactants has been used up (so the chemical reactions stop)
Question 2Medium5 marks
A student plans to investigate how the metal used for one electrode affects the voltage of a simple cell. The other electrode will always be copper, and the electrolyte will be copper sulfate solution.
(a) Identify the independent variable and the dependent variable.[2]
(b) Give two variables the student should control.[2]
(c) Suggest why the student should clean the surface of each metal electrode with sandpaper before use.[1]
Show the answer and mark scheme
(a)Answer: Independent: the metal used for the other electrode; dependent: the voltage of the cell.
independent variable: the metal used for the (non-copper) electrode
dependent variable: the voltage (potential difference) of the cell
(b)Answer: Concentration of copper sulfate solution; size (area) of the electrodes.
concentration of the copper sulfate solution
size (surface area) of the electrodes
distance between the electrodes
temperature
(c)Answer: To remove any oxide layer or dirt, which could otherwise affect the voltage.
to remove any oxide layer / dirt / grease from the surface, which could otherwise affect the reaction and the voltage measured
Question 3Hard4 marks
A simple cell is made from a zinc electrode and a copper electrode dipped into copper sulfate solution. Zinc is more reactive than copper. When the cell is used, the zinc electrode gets smaller and copper is deposited on the copper electrode.
(a) Write the half equation for the reaction at the zinc electrode.[1]
(b) Write the half equation for the reaction at the copper electrode.[1]
(c) Use the half equations to explain which electrode is the negative electrode of the cell.[2]
Show the answer and mark scheme
(a)Answer: Zn → Zn2+ + 2e−
Zn → Zn2+ + 2e−
(b)Answer: Cu2+ + 2e− → Cu
Cu2+ + 2e− → Cu
(c)Answer: Zinc is the negative electrode: it loses electrons, which then flow away from it through the external circuit.
zinc is the negative electrode
because zinc atoms lose electrons (are oxidised), and these electrons flow away from the zinc electrode through the external circuit