HSC Chemistry: the exam, the modules and practice questions with answers

Each daily paper has 8 original questions worth 25 to 35 marks. The Year 11 Chemistry paper revises the Year 11 modules, which the HSC treats as assumed knowledge, and its equilibrium, alcohols, hydrocarbons, naming and organic analysis questions are Year 12 content. The Year 12 Chemistry paper fits in its acids, bases and buffers, spectroscopy, polymers, amines, carbonyl and reaction pathway questions; skip rate equations, K_p, aromatic chemistry, transition metals and Born-Haber cycles, which are not in the HSC course.

The HSC Chemistry exam

That is NESA's exam specification. Practise with the real data sheet from that page so you know where the constants, solubility products and spectroscopy tables are. The 2027 HSC written exams run from Wednesday 13 October to Friday 5 November 2027; the timetable with each subject's date comes out on Friday 30 April 2027.

Your HSC mark is a 50:50 combination of the exam and your moderated school assessment. In Year 12, school assessment weights skills in working scientifically at 60% and knowledge and understanding at 40%. Band 6 is 90 to 100. NESA's new Chemistry 11 to 12 Syllabus (2025) is taught from 2028 and first examined in 2029, so the 2027 and 2028 HSCs use the 2017 modules below.

HSC Chemistry modules

HSC Chemistry practice questions with answers

We wrote these for this page, at least one per Year 12 module.

1. Equilibrium constant. For H₂(g) + I₂(g) ⇌ 2HI(g), the equilibrium concentrations are [H₂] = 0.10 mol/L, [I₂] = 0.10 mol/L and [HI] = 0.70 mol/L. Find K_eq. Answer: K_eq = [HI]² ÷ ([H₂][I₂]) = 0.49 ÷ 0.010 = 49. A K_eq well above 1 means products are favoured at this temperature.

2. Solubility product. Silver chloride has K_sp = 1.8 × 10⁻¹⁰ at 25 °C. What is its molar solubility? Answer: AgCl ⇌ Ag⁺ + Cl⁻, so K_sp = s², and s = √(1.8 × 10⁻¹⁰) = 1.3 × 10⁻⁵ mol/L. Adding chloride ions shifts the equilibrium left and lowers the solubility further: the common ion effect.

3. Titration. 25.0 mL of sodium hydroxide solution is neutralised by 18.6 mL of 0.100 mol/L hydrochloric acid. Find the concentration of the sodium hydroxide. Answer: n(HCl) = 0.100 × 0.0186 = 1.86 × 10⁻³ mol. The ratio is 1:1, so n(NaOH) is the same, and c = 1.86 × 10⁻³ ÷ 0.0250 = 0.0744 mol/L. Run the same titration in the Titration Lab.

4. pH of a strong acid. What is the pH of 0.020 mol/L hydrochloric acid? Answer: HCl ionises fully, so [H₃O⁺] = 0.020 mol/L and pH = −log₁₀(0.020) = 1.70. Check it with the pH Calculator.

5. Organic reaction pathways. Propan-1-ol and propan-2-ol are isomers. What does each give when oxidised with acidified potassium dichromate? Answer: propan-1-ol is a primary alcohol: it oxidises to propanal, then to propanoic acid. Propan-2-ol is secondary: it oxidises to the ketone propanone and no further.

Name the functional group family in our Organic Chemistry course, then press Mark.

6. Spectroscopy. A compound C₃H₆O₂ has a broad infrared absorption from 2500 to 3300 cm⁻¹ and a strong one near 1710 cm⁻¹. Its ¹³C NMR spectrum shows three peaks. Identify it. Answer: the broad band is an O-H in a carboxylic acid and the sharp one a C=O, so it is a carboxylic acid with three carbons in different environments: propanoic acid, CH₃CH₂COOH.

Use the daily papers as an HSC Chemistry trial

1. Open today's Year 12 Chemistry paper and work to the suggested time, 35 to 45 minutes, with the NESA data sheet beside you.
2. Skip the rate equation, K_p, aromatic, transition metal and Born-Haber questions.
3. Mark it and sort each lost mark by module.
4. For equilibrium and organic naming, sit the Year 11 Chemistry paper too, and use NESA's past HSC papers for full-length timing.

Common HSC Chemistry mistakes

• Putting solids or water in a K_eq expression. Leave out pure solids and liquids.
• Saying a catalyst shifts an equilibrium. It speeds up both directions equally, so the position doesn't change.
• Forgetting to convert mL to L in titration calculations.
• Oxidising a tertiary alcohol. Tertiary alcohols don't oxidise with acidified dichromate.
• Reading one spectrum alone. Combine IR, mass spectrum and NMR evidence before naming a compound.

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