Quick answer: A galvanic cell turns a spontaneous redox reaction into electricity: oxidation at the anode, reduction at the cathode. This Chemistry 11-12 test on electrochemical cells has 8 questions worth 20 marks, to do in 45 minutes: standard conditions, magnesium–silver cell and Iron(III) and iodide. The mark scheme is on a separate page; free printable PDF.
This test covers standard electrode potentials, cell emf, feasibility, fuel cells and electrolysis calculations. You have 45 minutes and may use a calculator. Show all working, use F = 96 500 C/mol and give units with every answer.
Level: Chemistry grades 11-12 (A Level · IB · Class 11-12) · Curriculum: IB R3.2
Question 1 Standard conditions (2 marks)
State two of the standard conditions needed to measure a standard electrode potential, and give the potential of the standard hydrogen electrode.Question 2 Magnesium–silver cell (3 marks)
Magnesium (E° = −2.37 V) and silver (E° = +0.80 V) half-cells are connected.- Calculate E°cell. (1 mark)
- Write the overall equation. (1 mark)
- State which electrode is the anode. (1 mark)
Question 3 Iron(III) and iodide (2 marks)
Predict whether Fe³⁺ ions oxidise iodide ions to iodine. E°: Fe³⁺/Fe²⁺ +0.77 V, I₂/I⁻ +0.54 V.Question 4 Refining copper (2 marks)
The diagram shows impure copper refined in copper(II) sulfate solution.- State at which electrode the copper dissolves. (1 mark)
- State at which electrode the mass increases. (1 mark)
Question 5 Nickel plating (3 marks)
A current of 1.50 A flows for 45.0 minutes in a nickel(II) plating bath (Ar Ni = 58.7; F = 96 500 C/mol). Calculate the mass of nickel deposited.Question 6 Hydrogen fuel cell (3 marks)
A hydrogen fuel cell has an acidic electrolyte.- Write the half-equations at the anode and the cathode. (2 marks)
- State one advantage of fuel cells over rechargeable batteries. (1 mark)
Question 7 The salt bridge (2 marks)
Explain what would happen to the voltmeter reading if the salt bridge were removed from a zinc–copper cell.Question 8 Brine electrolysis (3 marks)
Concentrated sodium chloride solution is electrolysed with graphite electrodes. Explain why hydrogen, not sodium, forms at the cathode, and name the product at the anode with an equation.
