A-LevelChemistryEquilibria9701/12 · Oct/Nov 2016 · Q111 Mark

Lithium reacts with nitrogen at room temperature to form solid Li₃N. Three vessels of equal volume are connected by taps, A and B, as shown. [Figure showing three connected vessels with taps A and B, contents are evacuated, N2(g) + 3H2(g) <=> 2NH3(g) at equilibrium, and Li] At the start, A and B are closed, the left-hand vessel is evacuated, the middle vessel has the indicated reaction at equilibrium and the right-hand vessel contains lithium only. Which action would allow the equilibrium mixture to contain the most ammonia?

This question uses a diagram from the original paper, which isn't shown here. Open the full paper from the past papers archive to see it.

AKeep both A and B closed.

BOpen both A and B.

COpen A only.

DOpen B only.

✓ Correct answer

A: Keep both A and B closed.

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Topic: Equilibria, A-Level Chemistry (syllabus 9701). Multiple choice, 1 mark.
Source: A-Level Chemistry, Oct/Nov 2016 Paper 1 Variant 2, question 11.

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