Oxidation and reduction
4 marks · NormalCopper(II) oxide reacts with hydrogen gas:
Identify the substance that is reduced and the substance that is oxidised in this reaction.
Name the oxidising agent and the reducing agent in this reaction.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
(a) Copper(II) oxide is reduced; hydrogen is oxidised. · must show CuO is reduced, H2 is oxidised
(b) Copper(II) oxide is the oxidising agent; hydrogen is the reducing agent. · must show CuO is the oxidising agent, H2 is the reducing agent
Common mistakes: incorrectly assigning agents; reversing oxidised/reduced
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Identifies copper(II) oxide as the substance reduced.
B2 (a) · 1 mark · Identifies hydrogen as the substance oxidised.
B3 (b) · 1 mark · Names copper(II) oxide as the oxidising agent.
B4 (b) · 1 mark · Names hydrogen as the reducing agent.
Worked solution
a:
Copper(II) oxide is reduced because it loses oxygen.
Hydrogen is oxidised because it gains oxygen.
b:
Copper(II) oxide is the oxidising agent (it oxidises hydrogen).
Hydrogen is the reducing agent (it reduces copper(II) oxide).