4.0 g of NaOH is dissolved to make 500 cm3 of solution. Calculate the concentration in mol/dm3. (Mr(NaOH) = 40)
[3 marks]
Total for this question: 3
All calculations
Concentration in mol/dm3
Quantitative chemistry
AQA 8462
ORIGINAL
Higher tier
c = n / V; n = m / Mr
Convert mass to moles first, then divide by the solution volume in dm3.
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
- Dividing the mass directly by volume without converting to moles.
- Forgetting that 500 cm3 is 0.500 dm3.
Exam tip: Write two equations on separate lines: n = m/Mr, then c = n/V.
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