How to use these DAT practice questions
The DAT is a computer-based, multiple-choice exam covering Survey of the Natural Sciences, Perceptual Ability, Reading Comprehension and Quantitative Reasoning. It rewards accurate decisions made quickly: knowing the core concept is only part of the task. You also need to identify the question type, remove weak choices, estimate when possible and move on when a question is consuming too much time.
Answer each question in the browser mock-up, then read the explanation. Do not judge your preparation only by the percentage correct. Record the reason for every miss:
- Knowledge gap: you did not know the relevant fact or relationship.
- Process error: you knew the concept but set it up incorrectly.
- Reading error: you misread the question or passage.
- Pacing error: you spent too long on a question that should have been triaged.
The set below mixes biology, general chemistry, organic chemistry, perceptual reasoning, reading and quantitative reasoning. The explanations model the short, ordered reasoning that helps under strict timing.
MySummaries puts questions beside the source material on your revision board, so a missed DAT concept can become a targeted card rather than an isolated score. Start with the first question.
Question 1 — General chemistry: stoichiometry
This tests whether you can convert the given mass to moles, apply the balanced equation and convert back without losing units.
How many grams of water are produced when 4.00 g of H2 reacts completely with excess O2? Use 2H2 + O2 → 2H2O. (H2 = 2.0 g/mol; H2O = 18.0 g/mol)
The correct answer is 18.0 g. Four grams of H2 is 2.0 mol H2. The equation gives a 1:1 mole ratio between H2 and H2O, so 2.0 mol H2O forms; 2.0 × 18.0 = 36.0 g. Therefore the correct option is actually 36.0 g, option 2. The strongest distractor is 18.0 g, which uses the molar mass of water but forgets that 2.0 mol are produced.
The worked calculation exposes an important issue: the marked answer and explanation must agree. In practice, a reliable question bank should not merely show a percentage; it should show the exact setup and the error pattern. The correct choice here is 36.0 g, so treat option 2 as the answer.
Question 2 — Biology: meiosis
This tests chromosome behaviour rather than memorisation of a single definition. Focus on what separates during each division.
During which stage of meiosis do homologous chromosomes, rather than sister chromatids, separate?
Anaphase I is correct: homologous chromosomes move to opposite poles while sister chromatids remain joined. Anaphase II separates sister chromatids. Prophase I includes synapsis and crossing over, while metaphase II aligns chromosomes but does not separate them.
For biology questions, use a compact sequence: identify the process, identify the objects moving, then match that event to the stage. This is faster than rereading every option as if it were a separate fact.
Question 3 — Organic chemistry: substitution
This asks you to connect substrate structure with the mechanism most favoured by the conditions.
Which substrate reacts most readily by an SN1 mechanism with ethanol as the solvent?
tert-Butyl bromide is correct because SN1 reactions proceed through a carbocation, and a tertiary carbocation is more stable than a secondary, primary or methyl carbocation. 2-Bromopropane is the strongest distractor because it can undergo SN1, but its secondary carbocation is less stable and reacts less readily under these conditions.
For mechanism questions, locate the leaving group, classify the carbon attached to it and then consider whether the solvent and nucleophile support the proposed pathway. Do not choose an answer simply because it is the largest molecule.
Question 4 — Perceptual Ability: angle ranking
This type of item rewards a repeatable visual method. Compare one feature at a time rather than trying to estimate the whole figure in a single glance.
Four angles are presented from smallest to largest: A, B, C and D. Angle A has arms separated by approximately 24°, B by 31°, C by 18°, and D by 27°. Which option gives the correct order from smallest to largest?
C is approximately 18°, A 24°, D 27° and B 31°, so C, A, D, B is the correct order. The strongest distractor is C, D, A, B: it reverses the middle comparison between 24° and 27°. Make that comparison directly instead of relying on the apparent length of the arms.
On perceptual items, avoid overthinking a close comparison after you have anchored two angles. If your first estimate is uncertain, compare the narrowest-looking pair directly and keep moving.
Question 5 — Reading Comprehension: passage purpose
This tests whether you can identify the passage’s central purpose rather than select a detail that happens to be mentioned.
Passage: Researchers initially attributed coral bleaching mainly to unusually warm water. Later experiments showed that heat disrupts the relationship between coral and its symbiotic algae, reducing energy transfer and increasing oxidative stress. The authors therefore argue that temperature is an important trigger, but the biological interaction explains much of the resulting damage. What is the main purpose of the passage?
The passage refines a simple explanation by linking heat to disruption of the coral–algae relationship and oxidative stress. That makes option 1 correct. Option 0 is the strongest distractor because warm water is identified as a trigger, but the passage explicitly says it is not the complete explanation.
Map the passage before chasing individual statements: topic, change or contrast, and author’s conclusion. For purpose questions, the correct choice usually covers the whole movement of the passage, not one supporting mechanism.
Question 6 — Quantitative Reasoning: percentage change
This tests percentage reasoning and estimation. Establish the original value before applying the change.
A solution is reduced from 240 mL to 180 mL. What is the percentage decrease?
The decrease is 60 mL. Divide by the original amount: 60/240 = 0.25, or 25%. Option 3 is the strongest distractor because 60/180 = 33⅓%, but percentage change uses the starting value as the denominator.
A quick check confirms the result: one quarter of 240 is 60, so a 25% decrease leaves 180. If an answer does not fit that estimate, revisit the denominator before doing more arithmetic.
Question 7 — Biology: enzyme activity
This tests interpretation of a standard enzyme graph and the distinction between denaturation and reversible inhibition.
An enzyme’s reaction rate rises as temperature increases from 10°C to 37°C, then falls sharply at 70°C. Which explanation best accounts for the fall at 70°C?
Denaturation changes the protein’s three-dimensional structure and can disrupt the active site, so option 1 is correct. Option 3 is the strongest distractor because the rate does peak at an optimum, but a sharp fall at a very high temperature is explained by structural damage rather than the enzyme simply reaching its optimum.
Graph questions often provide the concept visually. Identify the trend first, then ask what biological process could create that trend. Do not confuse the point of maximum activity with the cause of activity falling afterwards.
Question 8 — General chemistry: equilibrium
This tests the direction of a concentration shift using Le Châtelier’s principle.
For N2(g) + 3H2(g) ⇌ 2NH3(g), what happens when NH3 is removed from the reaction mixture at constant temperature?
Removing a product causes the system to shift right, producing more NH3 and consuming reactants. Option 0 is the strongest distractor because it reverses the response: adding NH3 would favour the left, whereas removing it favours the right. At constant temperature, the equilibrium constant does not change merely because concentrations change.
For equilibrium, label each change as reactant added, reactant removed, product added or product removed. Then shift towards the side that replaces what was removed or consumes what was added.
Question 9 — Organic chemistry: acidity
This tests stability of the conjugate base. More stable conjugate bases correspond to stronger acids.
Which compound is the most acidic?
Phenol is the most acidic because its conjugate base, phenoxide, is resonance-stabilised across the aromatic ring. Ethanol’s conjugate base lacks that resonance stabilisation, while ethane and ethene form very unstable carbanions. Ethanol is the strongest distractor because it also contains an O–H bond, but the surrounding structure makes its conjugate base less stable than phenoxide.
When comparing acidity, do not count heteroatoms or choose the molecule with the most complex structure. Draw or imagine the conjugate base and look for resonance, electronegativity and inductive effects.
Question 10 — Quantitative Reasoning: algebra and units
This tests whether you can isolate a variable while keeping the units and scale sensible.
A student walks at 1.5 metres per second for 8 minutes. How far does the student travel?
Convert 8 minutes to 480 seconds, then use distance = rate × time: 1.5 × 480 = 720 m. Option 1 is the strongest distractor because it multiplies 1.5 by 8 without converting minutes to seconds. The answer is also plausible: at roughly 1.5 m/s, several minutes should produce hundreds of metres, not tens.
Units are a built-in error check. Before selecting an answer, confirm that the units in the calculation match and estimate the order of magnitude. This catches many QR errors faster than repeating the calculation.
Review the set by error type
A score on its own does not tell you what to study next. Separate the misses by section and by cause. A candidate who misses two chemistry questions because of equilibrium reasoning needs a different intervention from one who knows the principle but loses time converting units.
Work on the lowest section first, but keep a short maintenance block for stronger sections. For a weak topic, complete three steps in one session:
- Relearn the smallest relevant concept from your notes.
- Answer several questions with a deliberate solution path.
- Repeat a similar question under a shorter time limit.
If the same concept is missed twice, it needs a more specific reminder than a general topic label.
You lost this mark twice: in an SN1 reaction, which carbocation stability pattern makes tert-butyl bromide more reactive than 2-bromopropane?
The remediation prompt should be answerable in one or two sentences. A useful response is: a tertiary carbocation is more stable than a secondary carbocation because alkyl groups stabilise the positive charge through inductive effects and hyperconjugation. If you cannot say that without guessing, return to the mechanism before adding more mixed questions.
A practical routine for the next question set
Use this sequence every time you practise:
- First pass: answer questions where the concept and setup are immediate.
- Decision point: if the route is unclear after a short inspection, flag the item rather than forcing it.
- Elimination: remove choices with wrong units, impossible magnitudes or a mechanism that contradicts the stem.
- Second pass: return to flagged items with the remaining time.
- Review: classify each error before opening another set.
For Perceptual Ability, the repeated skill is controlled comparison without excessive checking. For Reading Comprehension, it is passage structure and evidence. For science, it is core concept retrieval plus elimination. For Quantitative Reasoning, it is setup, units and estimation. Practise those behaviours explicitly rather than treating every wrong answer as a lack of knowledge.
How MySummaries helps
MySummaries can turn your DAT material into a revision board, then generate targeted flashcards, marked practice papers and audio explanations from that material. Its question workflow is most useful here when each missed item is linked to the relevant biology, chemistry, organic chemistry, PAT, reading or QR note, so your next review addresses the cause of the error. Start at portal.mysummaries.app.