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HSC Chemistry · Year 12

HSC Chemistry: what actually gets examined

Every question from 4 official NESA papers, coded by module, topic and marks — so you can decide what to revise from evidence rather than a feeling.

4 NESA papers, 2022–2025 · 174 questions · 400 marks

HSC Chemistry spreads its 400 marks over 16 topics, the biggest carrying 14%, and the 4 modules carry almost identical weight. There is nothing here you can safely skip — the question is what order you revise in.

Counted from 4 official NESA Chemistry papers (2022–2025). 174 questions, 400 marks. Nothing estimated.

16topics examined
54marks in the single biggest topic
20multiple choice marks, every paper
25%indicative weighting per module, quoted

The key words that carry the paper

Share of written-response questions by NESA key word, matched against NESA's own Glossary of Key Words. Revising the content without revising the directive is how marks get lost. The lower / middle / higher grouping is ours — NESA publishes the list but does not band it. Based on the 28% of written responses that open with a listed key word; the rest open with wording outside it, such as a direct question.

Explain35% · 9qmiddle order
Calculate27% · 7qlower order
Describe12% · 3qlower order
Other11% · 3q
Identify8% · 2qlower order
Outline8% · 2qlower order

Lower orderMiddle orderHigher order

Each tile is one key word; its size is that key word's share of written-response questions that open with one. The smallest 3 are grouped as Other: Analyse 4% · 1q, Construct 4% · 1q, Justify 4% · 1q.

Where the marks sit

Each module with its topics underneath. The bar is that topic's share of its own module.

Module 5: Equilibrium and Acid Reactions

107 marks

25% indicative weighting, quoted from the syllabus

Factors that Affect Equilibrium 29 marks

16 questions · 27% of this module · Practise →

Solution Equilibria 27 marks

12 questions · 25% of this module · Practise →

Calculating the Equilibrium Constant 26 marks

12 questions · 24% of this module · Practise →

Static and Dynamic Equilibrium 20 marks

10 questions · 19% of this module · Practise →

2 questions (6 marks) in this module were set across the whole module rather than on one topic. They are counted in the module total above, but they do not say which topics they examined — so the consistency chips are withheld here rather than guessed.

Concept pages in this module:

Study Module 5: Equilibrium and Acid Reactions →

Module 6: Acid/Base Reactions

99 marks

25% indicative weighting, quoted from the syllabus

Quantitative Analysis 54 marks

23 questions · 55% of this module · Practise →

Using Brønsted-Lowry Theory 22 marks

12 questions · 22% of this module · Practise →

Properties of Acids and Bases 21 marks

10 questions · 21% of this module · Practise →

1 question (4 marks) in this module was set across the whole module rather than on one topic. It is counted in the module total above, but it does not say which topic it examined — so the consistency chips are withheld here rather than guessed.

Concept pages in this module:

Study Module 6: Acid/Base Reactions →

Module 7: Organic Chemistry

98 marks

25% indicative weighting, quoted from the syllabus

Alcohols 26 marks

15 questions · 27% of this module · Practise →

Hydrocarbons 22 marks

15 questions · 22% of this module · Practise →

Reactions of Organic Acids and Bases 12 marks

5 questions · 12% of this module · Practise →

Products of Reactions Involving Hydrocarbons 11 marks

6 questions · 11% of this module · Practise →

Polymers 11 marks

8 questions · 11% of this module · Practise →

Nomenclature 6 marks

5 questions · 6% of this module · Practise →

4 questions (11 marks) in this module were set across the whole module rather than on one topic. They are counted in the module total above, but they do not say which topics they examined — so the consistency chips are withheld here rather than guessed.

Concept pages in this module:

Study Module 7: Organic Chemistry →

Module 8: Applying Chemical Ideas

97 marks

25% indicative weighting, quoted from the syllabus

Analysis of Inorganic Substances Every paper 45 marks

25 questions · 46% of this module · Practise →

Analysis of Organic Substances Every paper 31 marks

12 questions · 32% of this module · Practise →

Chemical Synthesis and Design Every paper 22 marks

8 questions · 23% of this module · Practise →

Concept pages in this module:

Study Module 8: Applying Chemical Ideas →

Across 4 papers the modules carried 107, 99, 98, 97 marks — against a 25% indicative weighting each, quoted from the NESA Chemistry Stage 6 Syllabus (2017). The counted share and the published weighting are two different measures.

How each topic gets asked

The 6 biggest topics, by the shape of the questions actually set on them. Revising the content without revising the directive is how marks get lost — the key words below are NESA's own, counted from the papers.

Quantitative Analysis

Module 6: Acid/Base Reactions · 54 marks across 23 questions

Asked as Multiple choice ×10 · Short answer ×10 · Extended response ×3

NESA key words Calculate ×2 · Explain ×1

Analysis of Inorganic Substances

Module 8: Applying Chemical Ideas · 45 marks across 25 questions

Asked as Multiple choice ×10 · Short answer ×15

NESA key words Calculate ×1 · Explain ×1 · Outline ×1 · Describe ×1 · Identify ×1

Analysis of Organic Substances

Module 8: Applying Chemical Ideas · 31 marks across 12 questions

Asked as Multiple choice ×6 · Short answer ×2 · Extended response ×4

NESA key words Describe ×1

Factors that Affect Equilibrium

Module 5: Equilibrium and Acid Reactions · 29 marks across 16 questions

Asked as Multiple choice ×7 · Short answer ×8 · Extended response ×1

NESA key words Explain ×3 · Identify ×1

Solution Equilibria

Module 5: Equilibrium and Acid Reactions · 27 marks across 12 questions

Asked as Multiple choice ×8 · Short answer ×1 · Extended response ×3

NESA key words Calculate ×1

Calculating the Equilibrium Constant

Module 5: Equilibrium and Acid Reactions · 26 marks across 12 questions

Asked as Multiple choice ×6 · Short answer ×5 · Extended response ×1

NESA key words Calculate ×1

What the markers wanted

NSW Education Standards Authority publishes per-question marking feedback after each paper. This is our reading of the 2022–2025 feedback, in our words, grouped by module and cited to the year and question it was seen in. It describes what markers rewarded in papers already sat; it does not predict the next one. The originals are linked below.

Across the paper

  • Every calculation should show each step, hold full precision until the final line, and finish with a unit and a sensible number of significant figures; early rounding was flagged in all four years.
  • Label what each line of working produces (moles, concentration, mass) so a multi-step titration, calorimetry or percentage-composition answer can be followed and credited.
  • Responses built on the numbers, graph or procedure supplied outscored those built on general recall; markers repeatedly noted stimulus data that went unused.
  • Graphs need a ruler, an even scale filling most of the grid, distinct symbols for each data set, a column graph for categorical variables, and an origin only where the data starts there.
  • Precise vocabulary carried marks: forward rate is not forward reaction, intermolecular is not intramolecular, and reactant or product side is safer than left or right.
  • Plan before writing so an extended response runs in a logical order, then check it against every part of the question before moving on.

Module 5: Equilibrium and Acid Reactions

Better responses

  • Explaining a disturbance through collision theory and the forward and reverse rates, then stating what happens to the concentration of the species asked about, not only the direction of the shift.
  • Writing the equilibrium expression first, with ion charges included and solids left out, then running an ICE table on the equation's mole ratios to reach the equilibrium concentrations.
  • Setting out solubility problems as a balanced dissolution equation, a Ksp expression with the right indices, moles converted to mol/L, and solid removed from the initial amounts before substituting.
  • Calculating Q from the given concentrations and comparing it with K, or the ionic product with Ksp, to decide whether a system sits at equilibrium or a precipitate forms.
  • Connecting a very large K to negligible reactants and a negative Gibbs free energy change to spontaneity, and treating enthalpy and entropy as fixed once equilibrium is established.

Where marks were lost — and how to keep them

  • Separating the position of equilibrium from the value of Keq: a system held at constant temperature keeps the same K even as concentrations change.
  • Treating a catalyst as raising both forward and reverse rates by the same factor, and a temperature drop as slowing both, with activation energy itself unchanged.
  • Defining equilibrium as equal forward and reverse rates rather than equal concentrations, and checking whether a graph axis reports moles or concentration.
  • Applying the reaction's mole ratio to the change row of an ICE table and to the indices in Ksp, then substituting carefully with order of operations respected.
  • Converting pH to pOH and then to hydroxide concentration inside an equilibrium calculation, and comparing Ksp values written in scientific notation correctly.

Seen in 2025 Q29, 2025 Q32, 2024 Q23, 2024 Q30, 2023 Q31, 2023 Q33, 2022 Q23, 2022 Q35.

Practise Equilibrium and Acid Reactions →

Module 6: Acid/Base Reactions

Better responses

  • Linking acid strength to degree of ionisation and so to hydronium concentration and pH, with an equilibrium arrow for a weak acid and a one-way arrow for a strong one.
  • Calorimetry set up with the combined mass of both solutions in q = mcΔT, mass and specific heat in matching units, and ΔH = -q/n reported as a negative value for neutralisation.
  • Titration work that discards the outlier before averaging, tracks the aliquot and dilution factor, applies the mole ratio from a balanced equation and rounds only at the end.
  • Finding Ka from a measured pH with an ICE table, or reading pKa from the half-equivalence volume on a titration curve, with the expression written out before substitution.
  • Writing balanced ionic equations with every charge shown when naming conjugate pairs or showing an amphiprotic ion reacting separately with an acid and with a base.

Where marks were lost — and how to keep them

  • Pairing each acid with its own conjugate base and keeping charges balanced when an amphiprotic species donates or accepts a proton.
  • Keeping units consistent through q = mcΔT (grams with J/g/K, joules with kilojoules) and carrying the negative sign into an exothermic ΔH.
  • Identifying the excess reactant after neutralisation, using the correct mole ratio for its ions, then moving from pOH to pH.
  • Relating strength to Ka and pKa rather than concentration alone, remembering the -log scale makes the relationship inverse, and not assuming a weak acid's concentration stays constant.
  • Recognising when a mixture is not a buffer, and explaining pH beyond the equivalence point by neutralisation and dilution rather than buffering.

Seen in 2025 Q34, 2024 Q28, 2024 Q36, 2023 Q24, 2023 Q35, 2022 Q22, 2022 Q26, 2022 Q32.

Practise Acid/Base Reactions →

Module 7: Organic Chemistry

Better responses

  • Drawing full structural formulae with every bond and hydrogen shown and four bonds on each carbon, including polymer sections with chain ends that continue.
  • Writing organic equations in structural formulae with reagent and conditions above the arrow: acidified dichromate or permanganate for oxidation, dilute acid catalyst for hydration.
  • Explaining boiling point and solubility trends by naming the intermolecular force, tying dispersion strength to chain length and hydrogen bonding to O or N, in cause-and-effect terms.
  • Justifying a structure by combining the molecular ion for molar mass, IR for functional groups, 13C NMR for carbon environments and 1H NMR shifts, integration and splitting.
  • Distinguishing addition from substitution, positional from functional group isomers, and primary from secondary alcohols, and tying each distinction to reactivity.

Where marks were lost — and how to keep them

  • Applying IUPAC naming in both directions: reading a prefix as chain length and a suffix as functional group, and naming a drawn product with the correct locants.
  • Continuing oxidation of a primary alcohol through the aldehyde to the carboxylic acid, and showing the hydroxyl group as C-O-H rather than a loose OH.
  • Explaining that boiling overcomes intermolecular forces without breaking covalent bonds, and keeping intermolecular and intramolecular as distinct terms.
  • Naming molecular shapes in full (trigonal planar, tetrahedral) and separating the shape of a molecule from its structural formula.
  • Combustion calorimetry that uses the mass of water heated, not the fuel, with q and ΔH in the same energy unit before dividing by moles.

Seen in 2025 Q27, 2025 Q37, 2024 Q24, 2024 Q38, 2023 Q25, 2023 Q36, 2022 Q21, 2022 Q27.

Practise Organic Chemistry →

Module 8: Applying Chemical Ideas

Better responses

  • Qualitative ion tests set out as a sequence: reagent, expected observation and a balanced equation with states for each step, guided by solubility rules or data-sheet Ksp values.
  • Quantitative answers that interpolate a calibration curve with a ruler, convert mg to g, apply the dilution factor and report a percentage to the right significant figures.
  • Spectroscopy justifications that tie each technique to a specific part of an annotated structure and reconcile the molecular ion peak with the calculated molar mass.
  • Synthesis and process designs naming specific reagents, conditions and equipment, with a structural-formula equation and yield tied to how the equilibrium is pushed.
  • Naming a precipitate with the metal's oxidation state (iron(III), not iron) and working backwards from a balanced equation to confirm a formula.

Where marks were lost — and how to keep them

  • Applying the mole ratio in the right direction when converting precipitate mass to percentage composition, with polyatomic ion molar masses correct.
  • Tracing a multi-step procedure: if two ions precipitate together and are filtered off, a later test gives a false result for the one not yet identified.
  • Linking each safety precaution to the specific hazard of the chemical used, and naming equipment correctly (fume hood), instead of listing generic PPE.
  • Separating accuracy from reliability, and quantitative from qualitative analysis, including gravimetric details such as drying to constant mass.
  • Reading a mass spectrum for the molecular ion and the base-peak fragment, and noticing carbonyl-adjacent carbons in 13C NMR and the broad COOH band in IR.

Seen in 2025 Q30, 2025 Q36, 2024 Q25, 2024 Q27, 2023 Q30, 2022 Q28, 2022 Q30, 2022 Q33.

Practise Applying Chemical Ideas →

2025 NESA marking feedback →2024 NESA marking feedback →2023 NESA marking feedback →2022 NESA marking feedback →

How the paper is built

Marks by question format across the same 4 papers.

Multiple choice 8020 / 20 / 20 / 20 per paper
Short answer 22554 / 54 / 61 / 56 per paper
Extended response 9526 / 26 / 19 / 24 per paper

Multiple choice is exactly 20 marks in every paper. The rest moves around: short answer ran 54, 54, 61, 56 marks and extended response ran 26, 26, 19, 24 marks. 4 papers is not enough to call that a trend.

Every question, by topic

All 174 questions from the 4 papers, listed under the topic each was coded to — year, question number, marks as printed on the paper, key word and format — with NESA's own copy of the paper linked on every row. The questions themselves are read there, not here. Marks here are as printed and every question is listed once, so these totals sit a little apart from “Where the marks sit” above, by design: there, a question coded to more than one topic has its marks split evenly. Open a module to see its list.

Module 5: Equilibrium and Acid Reactions48 questions · 108 marks · show

Factors that Affect Equilibrium · 16 questions, 32 marks

Solution Equilibria · 12 questions, 27 marks

Calculating the Equilibrium Constant · 11 questions, 22 marks

Static and Dynamic Equilibrium · 7 questions, 16 marks

Set across the whole module · 2 questions, 11 marks

Practise Equilibrium and Acid Reactions →

Module 6: Acid/Base Reactions40 questions · 97 marks · show

Quantitative Analysis · 19 questions, 48 marks

Using Brønsted-Lowry Theory · 10 questions, 19 marks

Properties of Acids and Bases · 10 questions, 23 marks

Set across the whole module · 1 question, 7 marks

  • 2024Q357 marksExtended responseshared with 1 other topicNESA paper →

Practise Acid/Base Reactions →

Module 7: Organic Chemistry54 questions · 115 marks · show

Alcohols · 15 questions, 30 marks

Hydrocarbons · 13 questions, 27 marks

Reactions of Organic Acids and Bases · 5 questions, 12 marks

Products of Reactions Involving Hydrocarbons · 4 questions, 8 marks

Polymers · 8 questions, 11 marks

Nomenclature · 5 questions, 6 marks

Set across the whole module · 4 questions, 21 marks

  • 2024Q387 marksExtended responseshared with 1 other topicNESA paper →
  • 2023Q28(a)2 marksDescribeShort answershared with 1 other topicNESA paper →
  • 2023Q28(b)3 marksShort answershared with 1 other topicNESA paper →
  • 2023Q369 marksExtended responseshared with 1 other topicNESA paper →

Practise Organic Chemistry →

Module 8: Applying Chemical Ideas32 questions · 80 marks · show

Analysis of Inorganic Substances · 19 questions, 41 marks

Analysis of Organic Substances · 8 questions, 20 marks

Chemical Synthesis and Design · 5 questions, 19 marks

Practise Applying Chemical Ideas →

The papers this is counted from

NSW Education Standards Authority publishes every paper and its marking guidelines. These links go to NESA's own copies — read the questions there.

2022 NESA paper · 100 marks →2023 NESA paper · 100 marks →2024 NESA paper · 100 marks →2025 NESA paper · 100 marks →

These are the external examination papers. They are not the whole subject: Chemistry is also assessed by school-based assessment set and marked by your school, which NESA does not publish — so nothing on this page covers that part of your result.

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Frequently Asked Questions

Which HSC Chemistry topics come up every year?

Not published for every module yet. 7 questions in the papers on file were set across a whole module rather than on one topic. Because they do not say which topics they examined, a topic that WAS examined could look absent — so the chips are withheld in the affected modules rather than guessed.

Which HSC Chemistry module is worth the most marks?

Module 5: Equilibrium and Acid Reactions 107, Module 6: Acid/Base Reactions 99, Module 7: Organic Chemistry 98, Module 8: Applying Chemical Ideas 97 marks across the 4 papers analysed. The syllabus publishes an indicative weighting for each; the counted share and the published weighting are two different measures.

What is the biggest single topic in HSC Chemistry?

Quantitative Analysis, with 54 of the 400 marks counted across 4 papers.

How was this analysed?

Every question in 4 official NESA HSC Chemistry papers (2022–2025) was counted against the NESA Chemistry Stage 6 Syllabus (2017): its mark value, its format and its key word, and the module and topic it assesses. Marks are reconciled against each paper's own stated total.

Are the exam questions reproduced here?

No. NSW Education Standards Authority owns the papers. This page publishes counts and links to NESA's own copy of each paper so you can read the questions at the source. The analysis is ours; the papers stay with NESA.

Does this predict what will be in my exam?

No, and it is not meant to. It describes what has been set. Examiners write each paper fresh and can weight a neglected topic heavily, which is why every topic is listed here, including the ones examined least.

Can I see which HSC Chemistry questions were set on each topic?

Yes. Every question from the 4 papers is listed above under the topic it was coded to, with its year, question number, marks and key word, and a link to NESA's copy of that paper. The question itself is read there, not here.

What did the NESA markers say about HSC Chemistry?

NSW Education Standards Authority publishes marker feedback after each paper. The "What the markers wanted" section above is our reading of it across 4 years, in our words, grouped by module and cited to the year and question it was seen in, with the originals linked.

Coded against the NESA Chemistry Stage 6 Syllabus (2017). Where a question is coded to more than one topic its marks are split evenly, so topic totals within a module can round a mark or two above the module total. Last updated 2026-09-01 · Exam papers © NSW Education Standards Authority, linked at source.