What you practice
Each set draws new burette close-ups, the way exam papers show them: a short stretch of scale with the meniscus. You read single burettes, turn initial and final readings into titres, complete a results table with a rough run, pick the concordant titres, work out the mean titre and its uncertainty, and at the top level go on to moles and concentration. Wrong answers that match a common slip get a note: reading the scale upward, reading the top of the meniscus, subtracting the wrong way, putting the rough titre in the mean, or writing 25.1 for 25.10.
Pick your exam board first. The boards agree on how to read a burette but not on everything after that, and each sheet prints its board's rules.
Example: a results table
In set MEANB5 (AQA) the rough run went from 1.50 to 26.05 cm³, a rough titre of 24.55. Titration 1 went from 0.35 to 24.60 (24.25), titration 2 from 0.05 to 24.30 (24.25), and titration 3 started where titration 2 ended, 24.30 to 47.75 (23.45). Titres 1 and 2 agree within 0.10 cm³, so they are concordant; titre 3 and the rough titre are left out. Mean titre = (24.25 + 24.25) ÷ 2 = 24.25 cm³, ±0.10 cm³, about 0.41%. Open set MEANB5
Questions
How do you read a burette?
Get your eye level with the bottom of the meniscus and read where the bottom of the curve sits. The numbers grow downward from 0.00 at the top, with lines every 0.1 cm³. A level on a line ends in 0 and one halfway between lines ends in 5, like 24.35 cm³.
Why are burette readings written to 2 decimal places?
You can judge half of a 0.1 cm³ division, so a reading ends in 0 or 5: 0.00, 23.45, 24.10. AQA, OCR, Edexcel and Cambridge want 2 decimal places, so 24 is written 24.00. US labs estimate the last digit instead, to 0.01 mL.
What are concordant titres?
Titres close enough to average. AQA and OCR use within 0.10 cm³. Edexcel's student guide and Cambridge mark schemes average titres within 0.20 cm³, and WAEC's published answers do too. NCERT asks for three concordant readings without giving a number. The rough titre never counts.
Is the rough titre included in the mean titre?
No. The rough titre only shows roughly where the end point is, so you can add the last drops slowly next time. Leave it out even when it happens to agree with the others.
What is the uncertainty of a titre?
Each burette reading is ±0.05 cm³, half a 0.1 cm³ division. A titre is final minus initial, two readings, so the uncertainties add: ±0.10 cm³. When AQA's handbook also counts the end-point drop (±0.05 cm³), the total is ±0.15 cm³.
How do you work out the percentage uncertainty of a titre?
Divide the uncertainty by the titre and multiply by 100. For 25.00 cm³: 0.10 ÷ 25.00 × 100 = 0.4%. A bigger titre gives a smaller percentage, which is why a more dilute solution in the burette helps.
How do I round the mean titre?
To 2 decimal places. When the exact mean ends in 5 in the third place, like 23.225, AQA's handbook writes 23.23 and Cambridge mark schemes accept 23.225 as it is. Edexcel's student guide rounds the mean to the nearest 0.05 cm³. This page accepts each of these.
Sources, read October 26, 2026: AQA A-level Chemistry practical handbook (PDF): half a division ±0.05 cm³ per reading, titre ±0.10, rough titre ignored, concordant within 0.10 cm³; AQA GCSE Chemistry required practicals (PDF): volumes to 2 dp; OCR AS and A Level Chemistry practical skills handbook, version 1.6: readings ending in 0 or 5, percentage uncertainty; Pearson Edexcel A level Chemistry practicals guide (PDF): titres within 0.20 cm³, mean to the nearest 0.05 cm³; Cambridge 9701/31 mark scheme, November 2017: readings including 0.00, mean to 2 dp; WAEC chief examiner's report, Chemistry 3, November 2012: table headings and the average titre; NCERT Laboratory Manual Chemistry XI, Unit 6 (PDF): observation table and concordant readings; LibreTexts, Calibration of a Buret and Florida State CHM3120L: buret readings to 0.01 mL.