Which HSC Chemistry past paper do students score lowest on?

The 2023 Exam, averaging 71.2% across 1,538 marked attempts on AusGrader. The 2025 Exam is the highest on 74.5%.

Which HSC Chemistry dot points give the best return on revision time?

8.2.2 (4.3 marks at risk per 100), 5.2.1 (3.6 marks at risk per 100) and 9.4.2 (3.0 marks at risk per 100). Marks at risk combines a dot point's share of paper marks with the marks students drop on it, so it ranks by recoverable marks and not by score alone.

How many attempts is each HSC Chemistry figure based on?

28,105 marked attempts overall, with the per-row count shown in every table. Any cut below 50 attempts is withheld instead of published.

Do these averages show how the NESA cohort performed?

No. They are AusGrader users' marked attempts, a self-selected group practising when they chose to and often without exam timing. They corroborate what NESA publishes about this subject and do not replace it.

HSC Chemistry hardest topics

Across 28,105 marked attempts on AusGrader, HSC Chemistry students average 58.4% on questions taken from board external papers. The lowest average of any command verb is draw on 54.0%, and the verb that costs the most marks is explain, which carries 22.0% of the paper against 7.0% for draw. These are self-selected users practising when they chose to, not the NESA cohort under exam conditions.

How to read these numbers

The figures are AusGrader users' marked attempts, not NESA results. They corroborate what the board publishes about this subject and do not stand in for it.
Any cut with fewer than 50 attempts is withheld, which on this page is 1 topic, 14 dot points and 20 verbs. Every figure shown carries its attempt count.
Scores cover questions mapped to the HSC Chemistry syllabus from any board's external papers, which is why the sample is larger than the 3 NESA papers alone. The paper table below is the exception and uses NESA papers only.
Internal assessment and school-uploaded exams are excluded throughout, so these averages differ from the ones on HSC Chemistry performance stats, which count every attempt.

Score by past paper

Year	Exam	Average	Attempts
2025	Exam	74.5%	882
2024	Exam	72.8%	784
2023	Exam	71.2%	1,538

The lowest average belongs to the 2023 Exam on 71.2% from 1,538 attempts, and the highest to the 2025 Exam on 74.5% from 882 attempts. A paper's average reflects both how hard it was and who chose to sit it, so treat the spread as a guide to which papers make demanding practice.

Score by question type

Question type	Average	Attempts
Extended response	49.0%	60
Multiple choice	56.3%	24,018
Short answer	63.6%	4,027

Score by module

Module	Average	Attempts
Module 8: Applying Chemical Ideas	53.9%	3,801
Module 9: Working Scientifically Skills	56.1%	6,445
Module 5: Equilibrium and Acid Reactions	56.5%	7,756
Module 7: Organic Chemistry	61.4%	10,758
Module 6: Acid/Base Reactions	62.0%	3,149

An attempt counts once per module, so a question assessed across two modules appears in both rows and the column adds to slightly more than 28,105.

The priority list: heavy topics with low scores

Topic	Share of marks	Average	Attempts	Marks at risk
Analysis of Organic Substances	9.4%	48.0%	2,061	4.9
Quantitative Analysis	11.2%	58.9%	1,938	4.6
Processing Data and Information	9.6%	54.5%	4,218	4.4
Factors that Affect Equilibrium	9.2%	55.8%	3,917	4.1
Calculating the Equilibrium Constant	6.3%	57.0%	1,741	2.7
Solution Equilibria	7.3%	66.9%	316	2.4
Using Brønsted–Lowry Theory	6.7%	68.3%	919	2.1
Analysis of Inorganic Substances	6.8%	70.3%	328	2.0
Alcohols	5.4%	63.1%	4,221	2.0
Reactions of Organic Acids and Bases	4.6%	61.8%	2,424	1.8
Properties of Acids and Bases	4.2%	61.2%	735	1.6
Static and Dynamic Equilibrium	3.2%	55.5%	3,247	1.4
Products of Reactions Involving Hydrocarbons	3.9%	65.1%	962	1.4
Chemical Synthesis and Design	2.8%	58.2%	1,454	1.2
Polymers	2.7%	59.4%	647	1.1
Hydrocarbons	2.6%	62.5%	2,240	1.0
Nomenclature	2.3%	58.3%	3,440	1.0
Conducting Investigations	0.7%	47.3%	222	0.4
Analysing Data and Information	0.8%	56.8%	2,271	0.3

The topic list is close: 4.9 against 4.6 marks at risk separates first from second, so topic choice alone will not order revision. The dot-point list below spreads further.

The same cut at dot-point level

Dot point	Content	Share of marks	Average	Attempts	Marks at risk
8.2.2	investigate the processes used to analyse the structure of simple organic compounds addressed in the course, including but not limited to: – proton and carbon-13 NMR – mass spectrometry – infrared spectroscopy (ACSCH130)	8.1%	46.7%	1,715	4.3
5.2.1	investigate the effects of temperature, concentration, volume and/or pressure on a system at equilibrium and explain how Le Chatelier’s principle can be used to predict such effects, for example: – heating cobalt(II) chloride hydrate – interaction between nitrogen dioxide and dinitrogen tetroxide – iron(III) thiocyanate and varying concentration of ions (ACSCH095)	7.4%	51.2%	2,824	3.6
9.4.2	apply quantitative processes where appropriate	6.4%	53.5%	3,726	3.0
5.3.2	perform calculations to find the value of $K_{eq}$ and concentrations of substances within an equilibrium system, and use these values to make predictions on the direction in which a reaction may proceed (ACSCH096)	5.6%	57.5%	1,302	2.4
5.4.4	derive equilibrium expressions for saturated solutions in terms of $K_{sp}$ and calculate the solubility of an ionic substance from its $K_{sp}$ value	4.5%	67.1%	195	1.5
7.3.1	investigate, write equations and construct models to represent the reactions of unsaturated hydrocarbons when added to a range of chemicals, including but not limited to: – hydrogen ( $H_2$ ) – halogens ( $X_2$ ) – hydrogen halides ( $HX$ ) – water ( $H_2O$ ) (ACSCH136)	3.4%	62.5%	616	1.3
6.3.4	calculate and apply the dissociation constant ( $K_a$ ) and $pK_a$ ( $pK_a = -\log_{10}(K_a)$ ) to determine the difference between strong and weak acids (ACSCH098)	4.2%	69.9%	282	1.3
9.4.1	select qualitative and quantitative data and information and represent them using a range of formats, digital technologies and appropriate media (ACSCH004, ACSCH007, ACSCH064, ACSCH101)	3.1%	59.2%	61	1.3
6.3.1	conduct practical investigations to analyse the concentration of an unknown acid or base by titration	2.7%	55.2%	1,087	1.2
6.3.2	investigate titration curves and conductivity graphs to analyse data to indicate characteristic reaction profiles, for example: – strong acid/strong base – strong acid/weak base – weak acid/strong base (ACSCH080, ACSCH102)	2.8%	57.4%	236	1.2
8.3.1	evaluate the factors that need to be considered when designing a chemical synthesis process, including but not limited to: – availability of reagents – reaction conditions (ACSCH133) – yield and purity (ACSCH134) – industrial uses (eg pharmaceutical, cosmetics, cleaning products, fuels) (ACSCH131) – environmental, social and economic issues	2.8%	58.2%	1,454	1.2
6.1.3	predict the products of acid reactions and write balanced equations to represent: – acids and bases – acids and carbonates – acids and metals (ACSCH067)	2.1%	57.8%	213	0.9
7.4.2	explain the properties within and between the homologous series of alcohols with reference to the intermolecular and intramolecular bonding present	1.8%	51.0%	805	0.9
8.1.2	conduct qualitative investigations – using flame tests, precipitation and complexation reactions as appropriate – to test for the presence in aqueous solution of the following ions: – cations: barium ( $Ba^{2+}$ ), calcium ( $Ca^{2+}$ ), magnesium ( $Mg^{2+}$ ), lead(II) ( $Pb^{2+}$ ), silver ion ( $Ag^+$ ), copper(II) ( $Cu^{2+}$ ), iron(II) ( $Fe^{2+}$ ), iron(III) ( $Fe^{3+}$ ) – anions: chloride ( $Cl^-$ ), bromide ( $Br^-$ ), iodide ( $I^-$ ), hydroxide ( $OH^-$ ), acetate ( $CH_3COO^-$ ), carbonate ( $CO_3^{2-}$ ), sulfate ( $SO_4^{2-}$ ), phosphate ( $PO_4^{3-}$ )	2.8%	72.5%	147	0.8
6.2.2	calculate pH, pOH, hydrogen ion concentration ( $[H^+]$ ) and hydroxide ion concentration ( $[OH^-]$ ) for a range of solutions (ACSCH102)	2.3%	67.6%	399	0.8
5.4.5	predict the formation of a precipitate given the standard reference values for $K_{sp}$	1.8%	59.2%	72	0.7

Which command verbs cost the most marks

Verb	Share of marks	Average	Attempts	Marks at risk
explain	22.0%	59.6%	1,195	8.9
calculate	19.7%	65.1%	499	6.9
justify	11.0%	55.6%	166	4.9
draw	7.0%	54.0%	351	3.2
identify	7.3%	59.8%	608	2.9
determine	6.0%	61.2%	356	2.3
outline	2.7%	70.1%	80	0.8
predict	2.3%	65.8%	102	0.8

Draw has the lowest average on the page at 54.0%, and it is not where the marks go. Explain averages 59.6% but carries 22.0% of the paper against 7.0%, so it puts 8.9 marks per 100 at risk against 3.2. Each verb above is practised in the HSC Chemistry question bank, where the marking criteria show what NESA expects the answer to do.

What this does not measure

Where to practise

Work the priority list from the top: Analysis of Organic Substances and Quantitative Analysis first, then the dot points above. Each topic page holds real NESA questions with marking criteria attached. For what the papers actually cover, read HSC Chemistry most tested topics.

Syllabus and assessment material referenced in this guide is used under licence, © Copyright NSW Education Standards Authority. See our NESA licensing notice. The NSW Education Standards Authority (NESA) does not endorse this product or service. NESA takes no responsibility for any errors in the reproduction of NESA Materials. Any sample examination papers or model answers accompanying the NESA Materials are not part of the NESA Materials and are in no way endorsed or authorised by NESA.