A-level titration stoichiometry
n = cV; use equation ratio; c = n/V
The aliquot volumes belong to different chemicals; attach each volume to its concentration before using the ratio.
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.
25.0 cm3 of 0.100 mol/dm3 H2SO4 neutralises 20.0 cm3 of NaOH. H2SO4 + 2NaOH → Na2SO4 + 2H2O. Calculate the NaOH concentration.
Do the calculation on paper first — then mark it.
Where the marks get lost
- Using a 1:1 ratio for a diprotic acid.
- Dividing by 20.0 instead of 0.0200 dm3.
Exam tip: Write the known chemical's n = cV line first and annotate the balanced equation with the resulting mole ratio.
Calculations are the most trainable marks in chemistry
They come up every paper and reward a clean method. Send me one you keep dropping marks on — your first lesson is free.