N2(g) + 3H2(g) → 2NH3(g). What volume of ammonia forms from 45 cm3 of hydrogen when nitrogen is in excess, at the same conditions?
[2 marks]
Total for this question: 2
All calculations
Reacting gas volumes
Quantitative chemistry
AQA 8462
ORIGINAL
Higher tier
gas volume ratio = balancing coefficient ratio
At the same temperature and pressure, gas volumes follow the balanced equation's mole ratio.
Board and spec code confirmed against AQA 8462 · registry checked 2026-07-17How this checking works
Work it, then mark it
Do each calculation on paper first, then reveal the mark scheme and tick the marks you actually earned — the same way you should mark past papers.
Q1
Do the calculation on paper first — then mark it.
Where the marks get lost
- Using formula subscripts instead of equation coefficients.
- Applying a gas-volume ratio to a solid or liquid reactant.
Exam tip: This shortcut works only for gases compared at the same temperature and pressure.
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