This is a full set of original, IB-style Paper 1B practice: a worked data set, dedicated uncertainty and graphing drills, two timed practice exams, and complete answer keys with explanations. Everything here is original material designed to mimic the reasoning style of Paper 1B; it does not reproduce copyrighted IB past-paper questions or markschemes.
New to Paper 1B, or want the theory and checklists behind these questions first? Start with the Paper 1B: Tips & Tricks guide, then come back here to practice.
How to Use Real Past Papers Alongside This Bank
This bank does not reproduce a bank of authentic IB past-paper questions, since those are only available through official IB channels. Use the following protocol once you've worked through this set and are ready to drill real past papers:
- Round 1 — Untimed: classify every question by skill (measurement / uncertainty / graph / technique / calculation / evaluation / chemistry interpretation).
- Round 2 — Timed: complete a full Paper 1B section under exam conditions.
- Round 3 — Error log: for every lost mark, record the exact failure: concept, reading, unit, algebra, graph, command term, or interpretation.
- Round 4 — Reattempt: redo the same question without looking at the markscheme.
- Round 5 — Markscheme language: identify what the accepted answer required, but do not memorize sentences; understand the scientific criterion.
- Round 6 — Transfer: write one new question testing the same skill with different numbers/context.
- Keep a "Paper 1B danger list" of recurring personal mistakes.
OFFICIAL PAST PAPERS — The Chemistry Guide states that past examination papers and markschemes can be purchased through the IB Store, and that additional resources such as specimen papers and subject reports are available through the Programme Resource Centre.
Full Original IB-Style Data Set
The following is an original practice set designed to mimic the reasoning style of Paper 1B without reproducing an IB past paper.
| [HCl] / mol dm⁻³ | Final CO₂ volume / cm³ | Time to reach 90% final volume / s |
|---|---|---|
| 0.20 | 42 | 78 |
| 0.40 | 79 | 54 |
| 0.60 | 116 | 43 |
| 0.80 | 119 | 35 |
| 1.00 | 120 | 31 |
a) Describe the relationship between HCl concentration and final CO₂ volume.
b) Describe the relationship between HCl concentration and the time required to reach 90% of the final volume.
c) What evidence suggests that increasing HCl affects rate and also affects final gas yield over part of the range?
d) Suggest one reason why the final volume might plateau.
Uncertainty Practice Bank
1. A balance reads 2.350 g with an uncertainty of ±0.005 g. Calculate the percentage uncertainty.
2. A volume is 25.00 ± 0.05 cm³. State the fractional uncertainty.
3. A titre is obtained from two burette readings, each ±0.05 cm³. State the absolute uncertainty in the delivered volume.
4. A result is 10.0 ± 0.2 units. State the percentage uncertainty.
5. A quantity x has 3% uncertainty and y has 2% uncertainty. For z = xy, state the simple propagated percentage uncertainty.
Graphing Practice Bank
- A graph is linear but does not pass through the origin. What does the intercept tell you? → There is a non-zero intercept; interpret it chemically only if the model/system gives it meaning.
- A data set has error bars that overlap strongly between two conditions. Can you automatically claim the means are significantly different? → No. Overlap indicates that the difference may be comparable with the stated uncertainty; stronger statistical claims require appropriate analysis.
- A student extrapolates far beyond the measured range to predict concentration. What is the main concern? → The relationship may not remain valid outside the measured range.
- A graph shows a curved relationship. Should the student force a straight line? → No. Use an appropriate non-linear model or transform variables only when scientifically justified.
- Why can R² be useful? → It provides a quantitative indication of how well a chosen trendline fits the data; it does not by itself establish causation or validate the experiment.
Calorimetry & Colorimetry Warm-Ups
A reaction heats 50.0 g of solution from 21.2 °C to 28.6 °C. Take c = 4.18 J g⁻¹ K⁻¹. Calculate q absorbed by the solution.
If the reaction itself is exothermic, what is the sign of ΔH for the reaction?
A student obtains titres 24.10, 24.15, 24.12 and 25.01 cm³. Which value should be investigated as a possible anomalous trial?
A 0.200 mol dm⁻³ stock solution is diluted to make 50.0 cm³ of a 0.0200 mol dm⁻³ solution. Calculate the stock volume required.
In a reaction producing CO₂, increasing HCl concentration increases the final gas volume from 80 cm³ to 120 cm³, then further increases in HCl leave the final volume at about 120 cm³. What does the plateau suggest?
Original Paper 1B Practice Exam — Set A
Designed to be completed without notes, under timed conditions. Answers appear later in the Answer Key, try every question first.
1. A student measures 25.00 cm³ of acid with a volumetric pipette and records four titres. What is the primary reason for using a pipette rather than a measuring cylinder?
2. A burette reading changes from 3.20 cm³ to 27.65 cm³. Calculate the delivered volume.
3. A titre of 24.35 ± 0.10 cm³ is obtained. Calculate the percentage uncertainty.
4. A graph of absorbance against concentration is linear from 0.00 to 0.080 mol dm⁻³ but becomes curved above 0.080 mol dm⁻³. Which procedure is most defensible for an unknown expected to be 0.120 mol dm⁻³?
5. A temperature change is measured as 7.4 ± 0.2 °C. Which change would most directly reduce random uncertainty in the temperature measurement?
6. A systematic error causes every mass measurement to be 0.20 g too high. Which statement is best?
7. A graph has a negative gradient. The measured concentration decreases with time. How should the rate of disappearance be reported?
8. A student writes "human error" as the only limitation of a titration. Why is this weak?
9. Which graph feature is most directly used to obtain an instantaneous rate at a selected point on a curve?
10. A set of repeated measurements is 15.1, 15.2, 15.1, 15.2, 15.1. What can be concluded most safely?
11. A reaction reaches the same final gas volume at 0.8 and 1.0 mol dm⁻³ HCl, but the 1.0 mol dm⁻³ reaction reaches it faster. What does this show?
12. A graph has x-axis labelled "time / 10² s." A point is at x = 3.0. What actual time does this represent?
Original Paper 1B Practice Exam — Set B
More demanding mixed data interpretation. Free-response, exam-style.
| Temperature / °C | Initial rate / arbitrary units | Mean rate uncertainty / arbitrary units |
|---|---|---|
| 20 | 1.8 | 0.1 |
| 30 | 3.0 | 0.1 |
| 40 | 4.8 | 0.2 |
| 50 | 7.1 | 0.3 |
| 60 | 10.2 | 0.4 |
1. Describe the trend in initial rate as temperature increases.
2. Explain, using collision theory, why increasing temperature can increase reaction rate.
3. A second experiment at 40 °C gives a rate of 5.9 units. Comment on this result relative to the original 40 °C mean and uncertainty.
4. Suggest one improvement that could reduce uncertainty in rate measurements caused by inconsistent timing.
5. The student claims that the rate doubles every 10 °C. Is this claim supported by the data? Justify.
Answer Key — Set A
| Question | Answer |
|---|---|
| 1 | A |
| 2 | A |
| 3 | A |
| 4 | B |
| 5 | A |
| 6 | B |
| 7 | B |
| 8 | A |
| 9 | B |
| 10 | A |
| 11 | A |
| 12 | C |
Answer explanations
- 1. A — A pipette is designed to deliver a fixed calibrated volume accurately; the other statements misdescribe its function.
- 2. A — 27.65 − 3.20 = 24.45 cm³.
- 3. A — (0.10/24.35) × 100 = 0.41%.
- 4. B — The unknown should be diluted into the range where the calibration relationship is supported rather than relying on unsupported extrapolation.
- 5. A — Repetition helps characterize/reduce random variation; it does not automatically remove systematic bias.
- 6. B — A constant bias can produce tightly clustered measurements that are nevertheless displaced from the true/accepted value.
- 7. B — For disappearance, the rate is normally reported as the positive magnitude of the decrease when requested as a rate.
- 8. A — A useful evaluation identifies the methodological issue and its effect.
- 9. B — Instantaneous rate at a point is obtained from the tangent gradient.
- 10. A — The values cluster closely, which supports precision. Accuracy requires comparison with an accepted/reference value.
- 11. A — The final amount is unchanged while the time to reach it decreases, so rate changes without a change in final amount over this range.
- 12. C — 3.0 × 10² s = 300 s.
Answer Guide — Set B
Keep Practicing
Revisit the Paper 1B: Tips & Tricks guide whenever a question here exposes a gap, then come back and re-attempt it cold before checking the answer again. That reattempt-without-looking step is what actually converts a mistake into a skill.