HSC Chemistry · Year 12 · 2019 to 2025 papers
What the last seven HSC Chemistry papers actually asked
Every question in the 2019 to 2025 HSC Chemistry examinations, sorted by topic, so you can see two different things that revision advice usually mashes together: which topics are near certain to appear, and which topics are where a Band 6 is decided. They are not the same list, and the difference changes what you should do with your last few weeks.
- Papers analysed
- 72019-2025
- Questions
- 302700 marks
- High yield topics
- 8of 60 labelled
- Band 6 topics
- 61 of them also high yield
The topics that are almost always on the paper
8 topics clear the high-yield rule set out at the bottom of this page. Between them they are the safest revision you can do, because the question is not whether they appear but how they will be asked.
| Topic | Marks | Papers | Marks per question | Band 6 |
|---|---|---|---|---|
| NMR, mass spectrometry and IR structure analysis Module 8 | 79 | 7 of 7 | 2.7 | Band 6 watch |
| Titration concentration analysis Module 6 | 50 | 7 of 7 | 4.2 | Band 6 |
| Ksp expressions and solubility calculations Module 5 | 32 | 7 of 7 | 2.3 | not Band 6 |
| Keq/concentration calculations and direction Module 5 | 30 | 6 of 7 | 2.5 | not Band 6 |
| Le Chatelier factors Module 5 | 27 | 7 of 7 | 1.8 | not Band 6 |
| Qualitative tests for aqueous ions Module 8 | 24 | 6 of 7 | 2.4 | Band 6 watch |
| Quantifying coloured species/metal ions Module 8 | 20 | 6 of 7 | 2.0 | Band 6 watch |
| Titration curves and conductivity graphs Module 6 | 19 | 7 of 7 | 1.7 | not Band 6 |
Where the Band 6 marks actually are
A topic can be certain to appear and still not be where the top band is decided. Only 1 of the 6 Band 6 topics is also high yield: Titration concentration analysis, at 50 marks and 4.2 marks a question. The others are worth knowing precisely because they are rare and large, not because they are likely.
| Topic | Marks | Papers | Marks per question | Yield |
|---|---|---|---|---|
| Titration concentration analysis Module 6 | 50 | 7 of 7 | 4.2 | HIGH |
| Factors in chemical synthesis/process design Module 8 | 23 | 5 of 7 | 3.8 | MEDIUM |
| Keq for ionic and acid/base dissociation Module 5 | 18 | 5 of 7 | 3.0 | MEDIUM |
| Enthalpy of neutralisation Module 6 | 18 | 4 of 7 | 3.6 | MEDIUM |
| Multistep reaction pathways and synthesis Module 7 | 18 | 4 of 7 | 3.6 | MEDIUM |
| Collision theory explanation of equilibrium changes Module 5 | 12 | 4 of 7 | 3.0 | MEDIUM |
7 further topics are on Band 6 watch: the demand is there, but the questions are small, so they rarely carry enough marks to separate the top band on their own. They are NMR, mass spectrometry and IR structure analysis, Ka and pKa; strong versus weak acids, Qualitative tests for aqueous ions, Quantifying coloured species/metal ions, Non-equilibrium systems, entropy and enthalpy, Buffer preparation and properties, Properties/bonding of acids, amines and amides.
9 topics sit in the middle band, short of the high-yield rule but more than a one-off: Ka and pKa; strong versus weak acids (24 marks, 5 of 7 papers), Factors in chemical synthesis/process design (23 marks, 5 of 7 papers), Keq for ionic and acid/base dissociation (18 marks, 5 of 7 papers), Enthalpy of neutralisation (18 marks, 4 of 7 papers), Multistep reaction pathways and synthesis (18 marks, 4 of 7 papers), Non-equilibrium systems, entropy and enthalpy (17 marks, 5 of 7 papers), Buffer preparation and properties (14 marks, 5 of 7 papers), Properties/bonding of acids, amines and amides (14 marks, 5 of 7 papers), Collision theory explanation of equilibrium changes (12 marks, 4 of 7 papers). Worth knowing. Not worth betting on.
The two rules, in full
So you can check a label rather than trust it.
High yield: will this be on the paper?
HIGH appears in >= 6 of 7 papers AND >= 15 marks total MEDIUM appears in >= 4 of 7 papers AND >= 10 marks total LOW everything else
Band 6 likely: is this where the marks separate?
YES average item >= 3.0 marks AND >= 50% of its marks are High-difficulty
or Analysis/Evaluation demand, AND >= 12 marks total
WATCH the demand share holds but the items are small
What this is not
- It is not a prediction. Seven papers is a small sample. A topic in four of seven may simply have been on a rotation, which is exactly why there is a middle band instead of one line between safe and unsafe.
- It is not a syllabus weighting. At paper level the four modules sit within a few marks of each other. These are topics inside modules, not modules.
- The Band 6 label leans on a judgement. Paper count, mark totals and question size are structural facts about the papers. Which questions counted as high difficulty is a teacher classification of demand, and the Band 6 label inherits that. It is a guide to where the long, discriminating questions have historically sat, not a NESA figure.
- Do not compare these numbers to Biology. The two subjects repeat themselves differently, so the thresholds differ, and a Chemistry high yield topic and a Biology one do not mean the same thing. Compare a topic only with others in its own subject.
- It cannot tell you what is coming. The long questions are consistently built on contexts nobody had seen before. Knowing the topic list is not the same as having practised applying it to an unfamiliar experiment or data set.
How to use this in the weeks you have left
- Start with the high yield table, not the Band 6 one. Marks you can guarantee are worth more than marks you might reach. Every topic in the first table appeared in at least four of the seven papers.
- Then take the one topic that carries both labels seriously. It is the only place where the near certain and the discriminating overlap, so it is the highest value hour on this page.
- Treat a "Band 6 watch" topic as a shape problem, not a content gap. Those topics ask the discriminating kind of thinking in small questions. The demand is real; the marks per question are not. Practise them for accuracy under time, not for depth.
- Do not spend your last week on the rare Band 6 topics. They are worth reading about if the rest is secure, and they are a poor bet if it is not. They appear rarely, and when they do they are large.
- Practise the shape, not just the content. Read the marks per question column. A topic averaging two marks is asking you to state and apply. A topic averaging four or more is asking you to analyse, justify and link, usually against data or an unfamiliar scenario.
Where to go next
Every module below is free to work through, with worked examples and practice questions.
How the numbers were produced
Every question in the 2019 to 2025 HSC Chemistry examinations was indexed by topic, marks, question type and demand, then the two rules above were applied to the totals. The underlying question-by-question workbook is not published, because it quotes examination material. The derived statistics on this page are generated directly from the analysis rather than typed in by hand, so the page and the analysis cannot drift apart.
Spotted something that looks wrong? Tell us. The rules are printed above precisely so a label can be argued with.