Chemistry, semester 1

CHEM191 practice questions

Cutline has exam-style CHEM191 practice questions with worked solutions. Course topics include bonding, equilibrium, acids and bases, kinetics, organic mechanisms, carbohydrates and amino acids. Check the published practice below for the worksheets currently available. You can start free without a card.

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1,825published MCQs

41worksheets and mock exams

As the catalogue lists them, checked 23 Oct 2026.

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Chemical EquilibriumSample 1 of 4
For the reaction $A(g) \rightleftharpoons 2B(g)$ , a graph is plotted of concentration vs. time. Which of the following describes the relative changes in concentration before equilibrium is reached?
Answer choicesA.The concentration of $B$ changes twice as much as the concentration of $A$ .B.The concentration of $A$ changes twice as much as the concentration of $B$ .C.The concentrations of $A$ and $B$ change by the exact same amount.D.The concentration of $B$ increases while the concentration of $A$ remains constant.
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Correct answer: A
Worked solution
The stoichiometry of the reaction (1 : 2) dictates the relative rates of change. For every 1 mole of $A$ consumed, 2 moles of $B$ are produced. Thus, the curve for $B$ has a steeper slope and undergoes a total concentration change twice as large as that of $A$ .
Mock 1Sample 2 of 4
One tablet of Panadol typically contains 500 mg of the active ingredient paracetamol ( $M = 151.16 \text{ g mol}^{-1}$ ). What amount (in moles) of paracetamol does one tablet contain?
Answer choicesA. $3.31 \times 10^{-3} \text{ mol}$ B. $75.6 \text{ mol}$ C. $6.62 \times 10^{-3} \text{ mol}$ D. $0.331 \text{ mol}$
Show answer
Correct answer: A
Worked solution
To find the amount in moles, use the formula $n = \frac{m}{M}$ . First, convert the mass from milligrams to grams: $500 \text{ mg} = 0.500 \text{ g}$ . Then divide by the molar mass: $n = \frac{0.500 \text{ g}}{151.16 \text{ g mol}^{-1}} = 3.307 \times 10^{-3} \text{ mol}$ .
Mock 1Sample 3 of 4
In the following reaction, $2H_2(g) + O_2(g) \to 2H_2O(g)$ , 0.50 mol of $H_2(g)$ and 1.00 mol of $O_2(g)$ are reacted together. Which of the following statements concerning this reaction is CORRECT?
Answer choicesA.The $H_2(g)$ is the limiting reactant.B.The $O_2(g)$ is the limiting reactant.C. $2.00 \text{ mol}$ of $H_2O(g)$ is produced.D.1.00 mol of $H_2O(g)$ is produced
Show answer
Correct answer: A
Worked solution
The balanced equation shows that 2 moles of $H_2$ react with 1 mole of $O_2$ . Thus, 0.50 mol of $H_2$ requires only 0.25 mol of $O_2$ to fully react. Since there is 1.00 mol of $O_2$ available, $O_2$ is in excess and $H_2$ is the limiting reactant.
Mock 1Sample 4 of 4
A stock solution of glucose has a concentration of $2.50 \text{ mol L}^{-1}$ . What volume of this stock solution is required to prepare $100.0 \text{ mL}$ of a $0.150 \text{ mol L}^{-1}$ glucose solution?
Answer choicesA. $6.00 \text{ mL}$ B. $60.0 \text{ mL}$ C. $16.7 \text{ mL}$ D. $37.5 \text{ mL}$
Show answer
Correct answer: A
Worked solution
Use the dilution equation $C_1V_1 = C_2V_2$ . Rearranging to solve for the initial volume gives $V_1 = \frac{C_2V_2}{C_1}$ . Substituting the values gives $V_1 = \frac{0.150 \text{ mol L}^{-1} \times 100.0 \text{ mL}}{2.50 \text{ mol L}^{-1}} = 6.00 \text{ mL}$ .

Published MCQ practice

Teaching practice and mock exams currently listed for this paper.

Teaching practice

Module 1: Reactions in Aqueous Solution
Worksheets: 9
MCQs: 413
- L1: StoichiometryMCQs: 72
- L2: Aqueous Solutions & SolubilityMCQs: 47
- L3: Chemical EquilibriumMCQs: 36
- L4: Solubility EquilibriaMCQs: 37
- L5: Acids and BasesMCQs: 50
- L6: Weak Acids, Bases, and pKaMCQs: 21
- L7: Buffer SolutionsMCQs: 88
- L8: Acid-Base TitrationsMCQs: 35
- L9: Molecules in Biological Environments (pH & Ionisation)MCQs: 27
Module 2: Energetics, Rates and Driving Forces in Chemical Reactions
Worksheets: 9
MCQs: 448
- L1: Thermodynamics: EnergeticsMCQs: 57
- L2: Chemical Thermodynamics Part 2MCQs: 48
- L3: Chemical Thermodynamics Part 3MCQs: 47
- L4: Chemical Kinetics Part 1MCQs: 57
- L5: Chemical Kinetics Part 2MCQs: 36
- L6: Chemical Kinetics Part 3MCQs: 35
- L7: Electron Transfer ReactionsMCQs: 70
- L8: Electron Transfer Reactions Part 2MCQs: 63
- L9: Electron Transfer Reactions Part 3MCQs: 35
Module 3: Structures and Reactions of Organic Molecules
Worksheets: 9
MCQs: 327
- L1: Atoms and Bonding Part 1MCQs: 34
- L2: Bonding, VSEPR and valence bond theoryMCQs: 33
- L3: Valence bond theory for organic moleculesMCQs: 34
- L4: Isomerism, Stereochemistry, Sigma/Pi bonds, and HybridisationMCQs: 24
- L5: Stereochemistry, Chirality, Enantiomers, and DiastereomersMCQs: 45
- L6: Introduction to Reaction Mechanisms Organic ReactionsMCQs: 40
- L7: Introduction to reaction mechanisms SubstitutionMCQs: 46
- L8: Substitution and EliminationMCQs: 35
- L9: Mechanisms of Addition ReactionsMCQs: 36
Module 4
Worksheets: 9
MCQs: 360
- L1: Biological Molecules and Functional GroupsMCQs: 36
- L2: Reactions of Carbonyl CompoundsMCQs: 32
- L3: MonosaccharidesMCQs: 54
- L4: Oligosaccharides and PolysaccharidesMCQs: 33
- L5: Reactions of Carboxylic Acid DerivativesMCQs: 44
- L6: Chemistry of Amino AcidsMCQs: 49
- L7: Peptides, Structure and FunctionMCQs: 36
- L8: Peptides, Stability and HydrolysisMCQs: 48
- L9: Aromatic compounds, Nucleosides, NucleotidesMCQs: 28

Mock exams

Progress Test Mocks
Mock exams: 3
MCQs: 119
- Mock 1MCQs: 39
- Mock 2MCQs: 40
- Mock 3MCQs: 40
Final Mocks
Mock exams: 2
MCQs: 158
- Mock 1MCQs: 80
- 2026 Variant 1MCQs: 78

Open CHEM191 catalogue

What this list includes. Active products only. Published worksheets in visible groups, with unrestricted multiple-choice questions. Retired questions, module tests and written questions are excluded. This does not measure whole-course coverage or concept articles. This catalogue is cached. The app rechecks access before you start. Checked 23 Oct 2026, 7:12 pm (UTC).

What this paper covers

These are paper topics, not a list of published worksheets.

atomic structure and bonding
chemical equilibrium
acids, bases and buffers
organic reaction mechanisms
thermodynamics and kinetics

How to approach CHEM191

the honest thing about chem191 is that the course itself does not give you much practice, and both exams are multi-choice. so the students who do well are usually the ones who have drilled enough questions to be fast and sure under time. use the published practice alongside your lecture notes to find what needs more work.

worth: 18 points (0.15 EFTS)
taught: semester 1, with a catch-up in summer school and semester 2
assessment: 20% mid-semester test, 10% lab tests, 70% final, both exams multi-choice

How to study CHEM191 (science-based)

These are established findings, not fringe claims, and recent reviews keep confirming them (Carpenter et al., 2022; Weinstein et al., 2018). The emphasis here is on the higher-order skill of applying and transferring ideas to unseen questions, which is what separates the top HSFY grades and the study habits medicine selects for.

chem191 is examined almost entirely by multiple-choice, and the course gives you very little practice built in, so the students who do well are the ones who train the exam skill deliberately rather than just rereading lecture slides. the methods below are drawn from cognitive science, and each one is matched to how chem191 tests you, from mechanisms to buffer calculations.

retrieve mechanisms, don’t reread them
the strongest finding in the study-technique literature is the testing effect: pulling information out of memory strengthens it far more than putting it back in by rereading. in a classic experiment, students who tested themselves on material remembered dramatically more a week later than students who restudied it for the same time (Roediger & Karpicke, 2006), and the large review by Dunlosky et al. (2013) rated practice testing as one of only two techniques with high utility across subjects and ages. the reason it matters for chem191 is that rereading a worked mechanism feels productive, but it only builds recognition, you can follow the arrows on the page while being unable to generate them yourself in the exam.
organic mechanisms are the clearest place to use this. a nucleophilic substitution or an acid-base mechanism is a sequence you can reconstruct from a blank page, which forces true retrieval rather than passive review. do it closed-book, then compare against the notes and correct only the steps you missed, because those missed steps are the precise gaps the exam will probe. the same applies to reaction outcomes and functional-group behaviour: predict first, check second. (Roediger & Karpicke, 2006; Dunlosky et al., 2013)
Try it: after a mechanism lecture, redraw the full curly-arrow pathway from memory on blank paper, then check it against the notes and fix only the steps you got wrong.
interleave the calculation types
most students study by blocking, doing a page of equilibrium problems, then a page of pH problems, then a page of thermodynamics. it feels smoother, but it hides the hardest skill: recognising which type of problem you are looking at. interleaving, deliberately mixing problem types in one session, forces you to choose the right method each time, and it reliably produces better performance on later tests even though it feels harder while you do it (Rohrer & Taylor, 2007).
chem191’s quantitative topics are perfect for this because equilibrium, acid-base and buffer, solubility, and Gibbs-energy questions all look superficially similar on the page. if you only ever practise them in labelled blocks, you learn to execute a method you have already been told to use, which is not what the exam asks. a mixed set trains the exam moment itself: read an unlabelled question, identify that it is a Ka calculation and not an equilibrium-position one, then solve it. (Rohrer & Taylor, 2007; Brunmair & Richter, 2019)
Try it: build a mixed set that jumps between a Ka calculation, a Gibbs-energy question and an equilibrium-position problem, so you practise identifying the type instead of grinding one kind.
explain why the reaction goes
self-explanation, asking yourself why each step happens and saying the answer in your own words, is one of the higher-utility strategies in the evidence review because it forces you to connect a fact to the principle underneath it rather than storing it in isolation (Dunlosky et al., 2013). the effort of generating the explanation is what builds understanding that transfers to unfamiliar questions.
chem191 is explicitly built around understanding why reactions proceed, not memorising outcomes, so this maps directly onto the exam. for a redox question, explain why the electrons move in that direction using reduction potentials; for an acid-base question, explain why one species is the stronger acid using structure and stability. once you can articulate the why, novel exam questions that dress up the same principle in new molecules stop being surprises. (Dunlosky et al., 2013)
Try it: for a redox or acid-base question, say out loud why the electrons or protons move the way they do before you look at the answer.
practise for transfer
the highest grades in chem191 do not go to the students who can recite the most, they go to the students who can apply a principle to a molecule or scenario they have never seen. this is called transfer, and the research is encouraging: retrieval practice, especially when you vary the problems, improves the ability to apply knowledge to new situations as well as memory for it (Pan & Rickard, 2018; Carpenter et al., 2022). it is directly relevant if you are aiming for medicine, where self-testing during study predicts later performance on medical licensing exams (Deng et al., 2015).
make your practice look like the exam, not the textbook. rather than reread a solved buffer problem, work fresh problems where the numbers and context change, and deliberately tackle questions that combine two ideas, an equilibrium that is also an acid-base system, for instance. the discomfort of applying a principle to an unfamiliar case is exactly the skill the multiple-choice distractors are built to test. (Pan & Rickard, 2018; Carpenter et al., 2022; Deng et al., 2015)
Try it: take a concept you have just learned and find or write a question that applies it in a context you have not seen, then solve it cold.

Flashcards, spaced repetition and Anki

The spacing effect is why flashcards work: revisiting a fact just as you are about to forget it locks it in far better than cramming (Cepeda et al., 2006). Anki is the tool most health-science students reach for, and it is good. turn each reaction mechanism and pKa fact into a card, and let spaced repetition resurface the ones you keep missing. Cutline pairs Anki-style flashcards for the raw facts with a qbank of exam-style CHEM191 questions, so you can drill what needs memorising and then practise applying it.

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Questions about CHEM191

is this the same chem191 that otago teaches?

yes, questions are written to match the otago chem191 lecture structure and exam style, lecture by lecture.

do i need to pay to start?

no, you can start free with no card, then upgrade only if you want the full bank.

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The evidence

The study methods above come from established research in cognitive and educational psychology.

Roediger, H. L., & Karpicke, J. D. (2006). Test-enhanced learning: Taking memory tests improves long-term retention. Psychological Science, 17(3), 249 to 255.
Dunlosky, J., Rawson, K. A., Marsh, E. J., Nathan, M. J., & Willingham, D. T. (2013). Improving students’ learning with effective learning techniques. Psychological Science in the Public Interest, 14(1), 4 to 58.
Rohrer, D., & Taylor, K. (2007). The shuffling of mathematics problems improves learning. Instructional Science, 35(6), 481 to 498.
Brunmair, M., & Richter, T. (2019). Similarity matters: A meta-analysis of interleaved learning and its moderators. Psychological Bulletin, 145(11), 1029 to 1052.
Pan, S. C., & Rickard, T. C. (2018). Transfer of test-enhanced learning: Meta-analytic review and synthesis. Psychological Bulletin, 144(7), 710 to 756.
Carpenter, S. K., Pan, S. C., & Butler, A. C. (2022). The science of effective learning with spacing and retrieval practice. Nature Reviews Psychology, 1(9), 496 to 511.
Deng, F., Gluckstein, J. A., & Larsen, D. P. (2015). Student-directed retrieval practice is a predictor of medical licensing examination performance. Perspectives on Medical Education, 4(6), 308 to 313.
Cepeda, N. J., Pashler, H., Vul, E., Wixted, J. T., & Rohrer, D. (2006). Distributed practice in verbal recall tasks: A review and quantitative synthesis. Psychological Bulletin, 132(3), 354 to 380.
Weinstein, Y., Madan, C. R., & Sumeracki, M. A. (2018). Teaching the science of learning. Cognitive Research: Principles and Implications, 3, 2.

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CHEM191 practice questions

Try a few real reps

Published MCQ practice

Teaching practice

Module 1: Reactions in Aqueous Solution

Module 2: Energetics, Rates and Driving Forces in Chemical Reactions

Module 3: Structures and Reactions of Organic Molecules

Module 4

Mock exams

Progress Test Mocks

Final Mocks