QCE Chemistry was completed by more than 9,300 Queensland students in 2025, and its external assessment is worth 50% of your final result. The 2025 exam tested electrolysis, titrations, green chemistry, weak and strong acids, amino acid electrophoresis and organic nomenclature, and QCAA's subject report shows exactly where students gained and lost marks.
This guide breaks down the external assessment section of QCAA's 2025 Chemistry subject report. It covers how every multiple-choice question was answered across the state, the short-response questions QCAA singled out, what effective responses did and QCAA's advice for future students. For the school-based side of the subject, see our companion breakdown of the 2025 QCE Chemistry internal assessments.
Key Takeaways
- 9,335 students completed Units 3 and 4 in 2025, a 6.76% increase on 2024, and 99.6% received a C or higher.
- An A required a final mark of 87 or more out of 100, and 44.26% of students achieved one.
- Students averaged 60.7% on the 20 multiple-choice questions. The hardest, Question 9, was answered correctly by only 30.65% of students.
- QCAA's biggest concern was chemistry conventions: ionic charges and states of matter, the right type of arrow for weak and strong acids, and correctly written oxidation states.
- QCAA also wants students to know specific reactions in detail: electrolysis under different conditions, hydrogen fuel cells in acidic and alkaline conditions, and organic reaction pathways.
The 2025 Cohort at a Glance
| Statistic | 2025 |
|---|---|
| Schools offering Chemistry | 423 |
| Students who completed Unit 1 | 11,322 |
| Students who completed Unit 2 | 10,451 |
| Students who completed Units 3 and 4 | 9,335 |
| Students who completed all 4 units | 82.45% |
| Change in enrolment since 2024 | +6.76% |
Source: QCAA Chemistry subject report, 2025 cohort.
Only 37 students received a D or E, so almost everyone who finishes Chemistry passes. With 44% of the cohort earning an A, the competition at the top is intense.
QCE Chemistry External Exam Structure
| Feature | Paper 1 | Paper 2 |
|---|---|---|
| Section 1 | 20 multiple-choice questions (20 marks) | Short-response questions (55 marks) |
| Section 2 | Short-response questions (35 marks) | – |
| Total | 55 marks | 55 marks |
The exam is worth 110 marks in total, which is converted to a mark out of 50 and makes up 50% of your final result. The other 50% comes from your three internal assessments: the data test (IA1, 10%), the student experiment (IA2, 20%) and the research investigation (IA3, 20%).
The most common external assessment results in 2025 fell between about 35 and 47 out of 50, with peaks around 41 and 45. Very few students scored 50.
💡 Get ready for the exam with our step-by-step guide on how to prepare for QCE external exams.
2025 Grade Boundaries and Results
| Grade | Final Mark (out of 100) | Number of Students | Percentage of Students |
|---|---|---|---|
| A | 87–100 | 4,132 | 44.26% |
| B | 72–86 | 3,671 | 39.33% |
| C | 50–71 | 1,495 | 16.01% |
| D | 20–49 | 36 | 0.39% |
| E | 0–19 | 1 | 0.01% |
Source: QCAA Chemistry subject report, 2025 cohort.
Your final mark is your internal assessment total (out of 50) plus your external assessment mark (out of 50). Final marks peaked between about 85 and 95, right on the A cut-off of 87, so every mark on the external exam matters.
Paper 1: Multiple-Choice Results
| Question | Correct Answer | % Correct | Most Common Wrong Answer |
|---|---|---|---|
| 1 | A | 56.01% | B (16.23%) |
| 2 | C | 60.55% | B (24.33%) |
| 3 | D | 46.21% | B (27.32%) |
| 4 | C | 79.04% | B (7.96%) |
| 5 | C | 62.75% | B (19.06%) |
| 6 | D | 57.07% | C (20.18%) |
| 7 | C | 81.21% | A (7.39%) |
| 8 | C | 53.33% | A (29.55%) |
| 9 | D | 30.65% | B (36.34%) |
| 10 | B | 56.00% | C (21.15%) |
| 11 | A | 57.78% | C (17.41%) |
| 12 | B | 32.42% | A (27.79%) |
| 13 | B | 71.68% | A (10.12%) |
| 14 | D | 57.85% | A (30.38%) |
| 15 | C | 75.05% | A (18.29%) |
| 16 | B | 68.15% | A (14.37%) |
| 17 | B | 93.62% | A (3.88%) |
| 18 | A | 84.43% | C (7.93%) |
| 19 | A | 43.87% | D (21.99%) |
| 20 | D | 46.76% | A (22.99%) |
Source: QCAA Chemistry subject report, 2025 cohort. Some students did not answer every question.
What the Multiple-Choice Results Show
- Question 9 was the hardest. More students chose B (36.34%) than the correct answer, D (30.65%), and C drew another 27%.
- Question 12 was almost evenly split. Only 32.42% chose the correct answer, B, and every other option drew 14–28% of students.
- Questions 8 and 14 each had one wrong option chosen by about 30% of students, which points to a common misconception.
- Questions 17 and 18 were answered correctly by more than 84% of students. These are marks you cannot afford to drop.
- Across the paper, students averaged 60.7%, so the typical student lost about 8 of the 20 multiple-choice marks.
💡 Check out why past papers are the best way to study for exams.
Short-Response Questions QCAA Highlighted
QCAA's report gave feedback and sample responses for six short-response questions.
Paper 1, Question 27: Electrolysis of Sodium Chloride
Students identified the cathode product and wrote the oxidation half-equation for the electrolysis of concentrated (25%) NaCl(aq) and molten NaCl(l).
| Electrolyte | Cathode Product | Oxidation Half-Equation |
|---|---|---|
| Concentrated NaCl(aq) | H₂(g) | 2Cl⁻(aq) → Cl₂(g) + 2e⁻ |
| Molten NaCl(l) | Na(l) | 2Cl⁻(l) → Cl₂(g) + 2e⁻ |
Key lesson: The conditions change the products. In aqueous solution, water is reduced at the cathode instead of sodium ions. Full marks also needed charges, states of matter and a forward arrow in each half-equation.
Paper 1, Question 28(c): Changing the Base in a Titration
Students predicted whether the pH at the equivalence point and the volume of HCl needed would change if a strong base replaced a weak base, and explained why.
Effective responses:
- stated that the equivalence point pH would rise to 7, because the titration is now strong acid with strong base
- stated that the volume of HCl would not change, because the number of moles of base to neutralise is the same
- supported this with a calculation: n(NaOH) = 0.2 × 0.01 = 0.002 mol, so V(HCl) = 0.002 ÷ 0.1 = 0.02 L = 20 mL.
Paper 1, Question 29(b): Evaluating Green Chemistry Pathways
Students evaluated three ways to produce benzaldehyde using atom economy and E-factor.
Effective responses calculated both measures for every method and reached a conclusion on each:
- the Na-MnOₓ catalyst pathway had the best atom economy (about 92% in the sample response)
- the Criegee oxidation pathway had the lowest environmental impact, with the lowest E-factor.
Key lesson: An evaluate question needs a systematic comparison of every option and a clear conclusion supported by evidence.
Paper 2, Question 4(a): Weak vs Strong Acid Dissociation
Students described the dissociation of HOCl(aq) and HCl(aq) using balanced equations.
Effective responses:
- HOCl(aq) + H₂O(l) ⇌ OCl⁻(aq) + H₃O⁺(aq), using a reversible arrow because HOCl is a weak acid that only partly dissociates
- HCl(aq) + H₂O(l) → Cl⁻(aq) + H₃O⁺(aq), using a forward arrow because HCl is a strong acid that fully dissociates.
Paper 2, Question 5(a): Amino Acids on an Electrophoresis Gel
Students identified three amino acids from their positions on a gel run in a buffer of pH 5, and explained their reasoning.
Effective responses compared each amino acid's isoelectric point with the buffer pH:
- glutamic acid (pI about 3.2) is below the buffer pH, so it loses H⁺, becomes negatively charged and moves towards the positive electrode
- arginine and cysteine have isoelectric points above 5, so they gain H⁺, become positively charged and move towards the negative electrode
- arginine, with the much higher isoelectric point, carries the greater positive charge and moves further.
Paper 2, Question 8(a): Structural Formulas and IUPAC Names
Students drew structural formulas and gave IUPAC names for two compounds. Effective responses identified Compound A as butanenitrile and Compound D as propan-1-ol, with correct structures.
What Students Did Well
QCAA said the 2025 cohort responded well to:
- describe and explain questions on redox and galvanic cells
- using spectroscopic data to tell apart functional groups such as ketones, aldehydes and carboxylic acids
- calculating pH and pKa, finding oxidation states, and drawing or naming structural isomers
- classifying acids and organic molecules from evidence, and contrasting the movement of ions and electrons in a galvanic cell
- inferring the nature of a reaction from Kc values, energy change and product formation, combining several data sources.
Areas QCAA Wants Students to Improve
1. Chemistry Conventions
QCAA wants students to communicate with correct conventions:
- include ionic charges and states of matter in redox equations
- use an equilibrium arrow (⇌) for the partial dissociation of weak acids and a forward arrow (→) for the full dissociation of strong acids
- write oxidation states with the sign first (+3) and ionic charges with the number first (2+).
2. Answering Every Part of the Question
Understand what the cognitive verb is asking for and use the mark value as a guide. QCAA's example: a 3-mark question asking for a prediction and an explanation usually needs a prediction plus two points of explanation.
3. Specific Reactions and Their Conditions
Learn these in detail:
- electrolysis of dilute, concentrated and molten salts
- how a hydrogen fuel cell works in acidic and alkaline conditions
- organic reaction pathways and the conditions each reaction needs.
💡 Not sure what "evaluate", "explain" or "determine" are asking for? Read our complete guide to QCE cognitive verbs.
How to Prepare for the QCE Chemistry External Exam
- Write equations with full conventions every time, including states, charges and the correct arrow.
- Make a table of electrolysis products for dilute, concentrated and molten electrolytes, and of fuel cell half-equations in acidic and alkaline conditions.
- Map out organic reaction pathways with the reagents and conditions for each step.
- Practise green chemistry calculations, such as atom economy and E-factor, and finish with a conclusion.
- Practise multiple choice under time pressure, checking each option carefully.
- Sit full past papers under timed conditions.
For more preparation:
- read our guide to getting an A in QCE Chemistry
- see our breakdown of the 2025 QCE Chemistry internal assessments
- read our 2025 QCE Biology external assessment breakdown
- check the QCE exam timetable 2026 for this year's exam dates
- learn how QCE subject scaling works.
Need Help With QCE Chemistry?
Our QCE Chemistry tutors work one-on-one with students to master equilibrium, redox and organic chemistry, and to write the precise equations and explanations QCAA markers look for.
Source: Queensland Curriculum & Assessment Authority, Chemistry subject report, 2025 cohort (January 2026).
