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IGCSE Chemistry Past Papers & Drilling (Paper 6): Titration and Analysis
TUTORZONE ORIGINAL DRILLING MOCK · CAMBRIDGE IGCSE CHEMISTRY (0620) PAPER 6 (ALTERNATIVE TO PRACTICAL)
Written to the Cambridge 0620 syllabus: Paper 6 Alternative to Practical, 1 h 15 min, 40 marks, 20%, all compulsory and testing practical and analytical skills; candidates also sit a multiple-choice paper (40 marks, 30%) and a theory paper (80 marks, 50%), and take EITHER Paper 5 Practical Test OR Paper 6, with the qualitative analysis notes provided for both. This is a Paper 6 drilling mock: 4 questions covering the 40 marks with answers and techniques.
What is in IGCSE Chemistry (0620) Paper 6?
Direct answer: Paper 6 Alternative to Practical, 40 marks, 1 h 15 min, 20%, all compulsory, testing titration, qualitative analysis, rates, gas tests and mole calculations on paper.
Assessment at a glance (2027)
| Component | Content | Weighting | Duration |
|---|---|---|---|
| Paper 6 (Alternative to Practical) | All compulsory, testing practical and analytical skills | 20% | 1 h 15 min |
| Paper 4 (Theory, Extended) | 80 marks | 50% | 1 h 15 min |
| Paper 2 (Multiple Choice, Extended) | 40 marks | 30% | 45 min |
| Paper 5 (Practical Test) | 40 marks, alternative to Paper 6 | 20% | 1 h 15 min |
IGCSE Chemistry 0620 Paper 6 drilling technique: decide which titres are concordant before averaging; give burette readings to two decimal places (0.05 cm^3); in qualitative analysis write the three steps – what is added, what is seen, which ion is deduced; in mole calculations write the equation and the mole ratio before substituting numbers and remember to convert cm^3 to dm^3 (divide by 1000); describe observations precisely (colour, whether a precipitate dissolves) rather than by smell.
How this paper was built
This is a TutorZone original drilling mock: the questions follow the Cambridge 0620 structure (Paper 6, 1 h 15 min, 40 marks, all compulsory) and the answers are our own, not Cambridge past papers or marking references.
Every numeric answer was computed independently before it was written (titre 23.80 cm^3, mean 23.80 cm^3, average rate 1.5 cm^3/s, sodium hydroxide 0.10 mol, concentration 0.40 mol/dm^3), so the key cannot drift from the question data.
Pacing
| Section | Marks | Suggested time | What to do first |
|---|---|---|---|
| Paper 6 (Alternative to Practical) | 20% | 15-18 min a question; readings and calculations first | readings, significant figures, units |
| Paper 4 (Theory, Extended) | 50% | do equations and mole calculations first | equations, moles, explanations |
| Paper 2 (Multiple Choice, Extended) | 30% | about a minute a question; calculations and practical items first | formulae, periodicity, practical |
| Paper 5 (Practical Test) | 20% | read the reagent notes and instructions first, then record observations as you go | hands-on work, recording, safety |
How should titration results be averaged?
Direct answer: find the readings that agree to within 0.05 cm^3 (concordant) and average only those, discarding any outlier.
Paper 6: 4 questions, 40 marks
All compulsory; burette readings to two decimal places and observations must be precise.
Question 1 (10 marks)
Question 1 (titration readings, 10 marks): the burette reads 0.50 cm^3 at the start and 24.30 cm^3 at the end. (a) Find the volume delivered. (b) Three titres are 23.70 cm^3, 23.80 cm^3 and 23.80 cm^3; find the mean to use and explain why the three are not simply averaged. (c) Give two practical errors that would make the titre too high.
Question 2 (10 marks)
Question 2 (qualitative analysis, 10 marks): a solution X gives a white precipitate with sodium hydroxide solution that dissolves in excess; a white precipitate with acidified silver nitrate solution that dissolves in dilute ammonia; and no precipitate with barium nitrate after dilute nitric acid. Deduce the ions in X and give two practical points to watch when using the reagents.
Question 3 (10 marks)
Question 3 (rate of reaction, 10 marks): marble chips react with dilute hydrochloric acid and 60.0 cm^3 of gas is collected in 40 seconds. (a) Find the average rate over this time. (b) Explain how the initial rate is found from a volume-time graph and how it differs from the average rate. (c) Give two ways to speed the reaction up and explain each.
Question 4 (10 marks)
Question 4 (gas tests and calculation, 10 marks): (a) Give the test and the positive result for hydrogen, oxygen and carbon dioxide. (b) 4.0 g of sodium hydroxide (Mr = 40) is dissolved to make 250 cm^3 of solution; find the concentration in mol/dm^3. (c) Explain why the qualitative analysis notes are provided with Paper 6.
How should qualitative analysis be written?
Direct answer: in three steps: what was added, what was seen (colour, whether it dissolves), which ion is deduced – no observation means no marks.
Paper 6 answers and working
Question 1
(a) 24.30 – 0.50 = 23.80 cm^3 (3). (b) The last two are within 0.05 cm^3 of each other (concordant), so average those two to get 23.80 cm^3; the first is 0.10 cm^3 away and is therefore inconsistent, so it is not included (4). (c) The burette was not rinsed with the solution (left-over water dilutes it), or the final reading was taken with the eye above the meniscus (parallax), or splashes on the flask wall were not washed down (3, any two).
Question 2
(a) A white precipitate with NaOH that dissolves in excess indicates Zn2+ (or Al3+); a white precipitate with acidified silver nitrate that dissolves in dilute ammonia indicates Cl-; no precipitate with barium nitrate confirms no sulfate, so X contains Zn2+ and Cl- (zinc chloride solution) (7). (b) Add reagents drop by drop and shake, watching whether the precipitate dissolves, and always acidify with dilute nitric acid before the silver nitrate test so that carbonate ions do not interfere (3).
Question 3
(a) 60.0 / 40 = 1.5 cm^3/s (3). (b) The initial rate is the gradient of the tangent at t = 0, because the concentration is highest and the reaction fastest at the start, whereas the average rate divides the total volume by the total time and therefore includes the slower later stage (4). (c) Break the marble into smaller chips so the surface area and the frequency of collisions rise, and increase the acid concentration or the temperature so the particles have more energy and collide more often (3).
Question 4
(a) Hydrogen: a lighted splint gives a squeaky pop; oxygen: a glowing splint relights; carbon dioxide: bubble it through limewater, which turns milky (6). (b) moles = 4.0 / 40 = 0.10 mol; concentration = 0.10 / (250 / 1000) = 0.40 mol/dm^3 (3). (c) Paper 6 tests the same analytical skills on paper, so the notes are given to let candidates explain observations and deductions rather than memorise the table (1).
Where do mole calculations usually go wrong?
Direct answer: unit conversion. Divide cm^3 by 1000 to get dm^3, and write the equation and mole ratio before substituting numbers.
Where these marks are usually lost
| Mistake | What it looks like | What it costs | Instead |
|---|---|---|---|
| Averaging all titres | Using every titre | The mean drifts | Average only the concordant titres |
| Too few decimal places | Writing 23.8 cm^3 | Marks deducted | Write 23.80 cm^3 |
| Vague observation | ‘A precipitate formed’ | No deduction marks | Colour and whether it dissolves |
| Forgetting the unit conversion | Using 250 cm^3 directly | Concentration ten times out | Divide by 1000 to get dm^3 |
How to use this paper
First drill: 1 h 15 min on all four questions with no textbook.
Mark it: check the decimal places, the averaging method and the three-step ion deduction.
Second drill: redo three to seven days later, and run a real titration and the gas tests in a lab.
What should I do after drilling this paper?
Direct answer: log every answer with wrong decimal places or a wrong mean; redo in three to seven days; then run a real titration and gas tests in the lab.
FAQ
Is this a Cambridge past paper?
No. The questions and answers are TutorZone originals, not Cambridge past papers or marking references.
How do Paper 6 and Paper 5 differ?
Both are 1 h 15 min, 40 marks and 20% and test the same skills; Paper 5 is hands-on while Paper 6 tests readings, observations, deductions and calculations on paper – you take one or the other, and both come with the qualitative analysis notes.
How should titres be averaged?
Check which readings agree to within 0.05 cm^3 (concordant) and average only those, discarding the one that differs.
What should I watch in answers?
Give burette readings to two decimal places, write the three steps of qualitative analysis (add, see, deduce), and write the equation and mole ratio before substituting numbers, converting cm^3 to dm^3.
Official references
| Resource | What to check |
|---|---|
| Cambridge IGCSE Chemistry 0620 page | Confirm the paper marks, times and weightings |
| https://www.tutorzone.com.hk/en-igcse-chemistry-0620-paper-4-mock-2027/ | IGCSE Chemistry Paper 4 drilling mock |
Related: practice area · IGCSE Chemistry Paper 4 drilling mock · IGCSE Physics Paper 6 drilling mock
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