Find my exam

PCAT Practice Questions (2026) — Free Sample Questions with Answers

6 free PCAT questions from our 25-question bank, grouped by content domain. Each answer explains why the right option is right — and why every wrong option is wrong.

Biological Processes (1)Chemical Processes (2)Critical Reading (1)Quantitative Reasoning (1)Writing (1)
0 of 6 answered — answer a question to check it Take a full PCAT practice test

Biological Processes

Question 1

During which phase of mitosis do sister chromatids separate and move toward opposite poles of the cell?

Show answer & explanation

Answer: C

Prophase: In prophase, chromosomes condense and the spindle begins to form; the chromatids are still joined.

Metaphase: In metaphase, chromosomes line up at the metaphase plate; separation has not yet begun.

Anaphase: Correct. In anaphase, cohesin is cleaved and kinetochore microtubules pull sister chromatids to opposite poles.

Telophase: In telophase, the separated chromosomes have already reached the poles and nuclear envelopes re-form.

Mitosis order: prophase (condense) → metaphase (align) → anaphase (separate) → telophase (re-form nuclei), followed by cytokinesis.

Chemical Processes

Question 2

For the gas-phase reaction N₂(g) + 3 H₂(g) ⇌ 2 NH₃(g), ΔH < 0. Which change would increase the equilibrium yield of NH₃?

Show answer & explanation

Answer: D

Raising the temperature of the mixture: The forward reaction is exothermic, so raising temperature shifts equilibrium toward reactants.

Adding an iron catalyst to the vessel: A catalyst speeds the approach to equilibrium but does not change the equilibrium position or yield.

Lowering pressure by enlarging the vessel: Lower pressure favors the side with more gas moles (4 mol of reactants), reducing NH₃.

Raising pressure by shrinking the vessel: Correct. Higher pressure favors the side with fewer moles of gas (2 mol NH₃ vs. 4 mol reactants), shifting equilibrium to the right.

Le Chatelier: pressure increase → fewer gas moles; temperature increase → endothermic direction; catalysts change rate, not position.

Question 3

Methane burns completely according to CH₄ + 2 O₂ → CO₂ + 2 H₂O. How many grams of water are produced when 16 g of methane burns in excess oxygen? (Molar masses: CH₄ = 16 g/mol; H₂O = 18 g/mol; CO₂ = 44 g/mol.)

Show answer & explanation

Answer: B

18 g: This assumes a 1 : 1 mole ratio; the balanced equation gives 2 mol H₂O per mol CH₄.

36 g: Correct. 16 g CH₄ = 1.0 mol, producing 2.0 mol H₂O × 18 g/mol = 36 g.

44 g: 44 g is the mass of CO₂ produced, not water.

72 g: This doubles the correct answer, as if 4 mol of water formed per mole of methane.

Stoichiometry route: grams → moles (÷ molar mass) → mole ratio from the balanced equation → grams of product.

Critical Reading

Question 4

Passage: Adolescents are often accused of laziness for sleeping late, but biology offers a different explanation. During puberty, the timing of melatonin release shifts later, so many teenagers do not feel sleepy until well after 11 p.m. Since most still need roughly eight to ten hours of sleep, an early school bell guarantees a chronic shortfall for many students.

Several districts that delayed their start times reported that students slept longer, and some saw fewer late arrivals and better attendance. Opponents point to costs: bus schedules must be reorganized, and after-school jobs and sports may run later into the evening. These costs are real, but they are logistical problems with logistical solutions. The sleep deficit imposed by early start times, by contrast, cannot be scheduled away by students themselves, because it arises from a biological clock they do not control.

The author's argument assumes that:

Show answer & explanation

Answer: B

students who sleep longer will necessarily earn higher grades: The author cites sleep, tardiness and attendance, not grades, so this is not required by the argument.

the costs of later start times can be resolved through planning: Correct. Calling the costs 'logistical problems with logistical solutions' takes for granted that they can be solved without unacceptable trade-offs.

every district in the country should adopt one shared start time: The author argues for later start times, not a single uniform time across districts.

teenagers need less total sleep than adults do each night: The passage says teenagers need roughly eight to ten hours and makes no comparison with adults.

An assumption is an unstated belief the argument relies on; look for claims asserted without support, such as dismissing costs as easily solvable.

Quantitative Reasoning

Question 5

If f(x) = (3x² + 1)⁴, what is f′(x)?

Show answer & explanation

Answer: D

4(3x² + 1)³: This applies the power rule to the outer function but omits multiplying by the inner derivative, 6x.

6x(3x² + 1)⁴: This multiplies by the inner derivative but does not apply the power rule to the outer function.

12x(3x² + 1)³: This uses 3x as the inner derivative; the derivative of 3x² + 1 is 6x.

24x(3x² + 1)³: Correct. Chain rule: 4(3x² + 1)³ × 6x = 24x(3x² + 1)³.

Chain rule: d/dx[g(h(x))] = g′(h(x)) · h′(x) — differentiate the outside, keep the inside, multiply by the inside's derivative.

Writing

Question 6

Which revision corrects the grammatical error in this sentence? 'The results of the study, which included patients from three hospitals, suggests that the new discharge protocol reduces readmissions.'

Show answer & explanation

Answer: D

The results of the study, which include patients from three hospitals, suggests that…: Changing 'included' to 'include' does not fix the main error: the plural subject 'results' still has the singular verb 'suggests'.

The results of the study; which included patients from three hospitals, suggests that…: A semicolon cannot introduce a dependent clause, and the subject–verb error remains.

The results of the study which included patients from three hospitals suggests that…: Removing the commas changes the punctuation only; 'results… suggests' is still a subject–verb disagreement.

The results of the study, which included patients from three hospitals, suggest that…: Correct. The subject is 'results' (plural), so the verb must be 'suggest'; the nonessential clause about the study does not change the subject.

Find the true subject by skipping prepositional phrases ('of the study') and nonessential clauses; then match the verb to it.

Test yourself under exam conditions

Take the free PCAT test and get a score report by domain.

Start free PCAT test
The full PCAT question bank is coming. Get an email when it launches.