Which topic carries the most marks in the WACE Chemistry external exam?

Properties and structure of organic materials carries 28.2% of the marks across the 6 SCSA papers from 2020 to 2025, ahead of Acids and bases on 17.3%.

How are marks split between question types in the WACE Chemistry exam?

Short answer carries 63.8% of the marks, extended response carries 23.2% of the marks and multiple choice carries 13.0% of the marks, measured across 6 papers and 1152 marks from 2020 to 2025.

Has the topic balance changed in recent WACE Chemistry papers?

Yes. Properties and structure of organic materials moved down 3.4 percentage points, Acids and bases moved up 4.9 percentage points, Chemical equilibrium systems moved down 3.5 percentage points, Oxidation and reduction moved up 5.0 percentage points, Chemical synthesis moved up 5.6 percentage points, Science Inquiry Skills (Unit 3) moved down 5.2 percentage points and Science Inquiry Skills (Unit 4) moved down 3.4 percentage points between the 2020 to 2022 and 2023 to 2025 papers.

How many past papers is this WACE Chemistry analysis based on?

6 SCSA external papers from 2020 to 2025, covering 237 questions and 1152 marks. 0.8% of those marks carry no dot-point mapping and sit outside the percentages.

WACE Chemistry most tested topics

Across the six SCSA Chemistry external papers from 2020 to 2025, Properties and structure of organic materials carries 28.2% of the marks against 1.7% for Science Inquiry Skills (Unit 4), so the paper rewards Properties and structure of organic materials more than any other topic. At dot-point level 3.3.2.11 carries 6.3% of paper marks, and two of the 76 dot points that the board assesses externally have not appeared in one of these papers. Every percentage below covers the 99.2% of marks that map to a syllabus dot point.

Computed from 6 SCSA Chemistry external papers, 2020 to 2025: 237 questions, 423 question parts and 1152 marks.

Unit, topic and dot-point shares below are of the 1143 marks that map to a dot point, so each of those tables adds to 100%. 145 of the 423 parts are assessed against more than one dot point, and their 492 marks are divided evenly between the dot points they cover.

What these papers are

Year	Exam	Questions	Marks
2025	Exam	40	203
2024	Exam	40	193
2023	Exam	39	190
2022	Exam	39	186
2021	Exam	39	191
2020	Exam	40	189

Marks by unit

Unit	Share of marks
Unit 3: Equilibrium, acids and bases, and redox reactions	56.2%
Unit 4: Organic chemistry and chemical synthesis	43.8%

Marks by topic

Topic	Share of marks	Papers it appears in	Years
Properties and structure of organic materials	28.2%	6 of 6	6 of 6
Acids and bases	17.3%	6 of 6	6 of 6
Chemical equilibrium systems	16.5%	6 of 6	6 of 6
Oxidation and reduction	14.7%	6 of 6	6 of 6
Chemical synthesis	13.9%	6 of 6	6 of 6
Science Inquiry Skills (Unit 3)	7.7%	6 of 6	6 of 6
Science Inquiry Skills (Unit 4)	1.7%	3 of 6	3 of 6

Marks by subtopic

Each topic above breaks into the subtopics below, in the same order.

Subtopic	Share of marks	Papers
Science Understanding (Properties and structure of organic materials)	28.1%	6 of 6
Science as a Human Endeavour (Properties and structure of organic materials)	0.1%	1 of 6
Science Understanding (Acids and bases)	16.7%	6 of 6
Science as a Human Endeavour (Acids and bases)	0.6%	4 of 6
Science Understanding (Chemical equilibrium systems)	15.5%	6 of 6
Science as a Human Endeavour (Chemical equilibrium systems)	1.0%	4 of 6
Science Understanding (Oxidation and reduction)	13.8%	6 of 6
Science as a Human Endeavour (Oxidation and reduction)	0.9%	4 of 6
Science Understanding (Chemical synthesis)	13.3%	6 of 6
Science as a Human Endeavour (Chemical synthesis)	0.5%	4 of 6

Marks by dot point

Dot-point numbers and wording are SCSA's own. Where a dot point is written as a list, its items run together here separated by semicolons.

Dot point	Content	Topic	Share of marks	Papers
3.3.2.11	data obtained from acid-base titrations can be used to calculate the masses of substances and concentrations and volumes of solutions involved	Acids and bases	6.3%	6 of 6
4.2.2.9	empirical and molecular formulae can be determined by calculation and the structure of an organic compound established from the chemical reactions they undergo, and other analytical data	Properties and structure of organic materials	5.3%	6 of 6
3.2.2.9	the effects of changes in temperature, concentration of species in solution, partial pressures of gases, total volume and the addition of a catalyst on equilibrium systems can be predicted using Le Châtelier’s Principle	Chemical equilibrium systems	4.2%	6 of 6
3.1.0.1	use science inquiry skills to design, conduct, evaluate and communicate investigations into the properties of acids and bases, redox reactions and electrochemical cells, including volumetric analysis	Science Inquiry Skills (Unit 3)	4.0%	6 of 6
4.3.2.2	quantities of products in a chemical synthesis reaction can be calculated by comparing stoichiometric quantities with actual quantities and by determining the limiting reagent	Chemical synthesis	3.8%	4 of 6
4.2.2.8	organic compounds display characteristic physical properties, including boiling point and solubility in water and organic solvents; these properties can be explained in terms of intermolecular forces (dispersion forces, dipole-dipole interactions and hydrogen bonds) which are influenced by the nature of the functional groups	Properties and structure of organic materials	3.8%	6 of 6
3.2.2.1	collision theory can be used to explain and predict the effects of concentration, temperature, pressure, the presence of catalysts and surface area of reactants on the rates of chemical reactions	Chemical equilibrium systems	3.7%	6 of 6
3.1.0.3	communicate, predict and explain chemical phenomena using qualitative and quantitative representations in appropriate modes and genres	Science Inquiry Skills (Unit 3)	3.7%	4 of 6
3.3.2.5	buffer solutions are conjugate in nature and resist changes in pH when small amounts of strong acid or base are added to the solution; buffering capacity can be explained qualitatively; Le Châtelier’s Principle can be applied to predict how buffers respond to the addition of hydrogen ions and hydroxide ions	Acids and bases	2.6%	6 of 6
3.4.2.2	oxidation involves the loss of electrons from a chemical species, and reduction involves the gain of electrons by a chemical species; these processes can be represented using half-equations and redox equations (acidic conditions only)	Oxidation and reduction	2.4%	6 of 6
4.3.2.9	the cleaning action of soaps and detergents can be explained in terms of their non-polar hydrocarbon chain and charged group; the properties of soaps and detergents in hard water can be explained in terms of the solubilities of their calcium salts	Chemical synthesis	2.3%	5 of 6
3.2.2.3	observable changes in chemical reactions and physical changes can be described and explained at an atomic and molecular level	Chemical equilibrium systems	2.1%	6 of 6
4.2.2.6	all alcohols can undergo complete combustion; with oxidising agents, including acidified $MnO_4^-$ or $Cr_2O_7^{2-}$ oxidation of primary alcohols produces aldehydes and carboxylic acids, while the oxidation of secondary alcohols produce ketones; these reactions have characteristic observations and can be represented with equations	Properties and structure of organic materials	2.1%	6 of 6
3.4.2.9	electrochemical cells can be described in terms of the reactions occurring at the anode and cathode, the role of the electrolyte, salt bridge (galvanic cell), ion migration, and electron flow in the external circuit	Oxidation and reduction	2.1%	6 of 6
3.4.2.10	corrosion of iron is an electrochemical process that can be prevented by a range of techniques, including by exclusion of oxygen and/or water and through cathodic protection and sacrificial anodes	Oxidation and reduction	2.1%	4 of 6
3.4.2.3	a range of reactions involve the oxidation of one species and reduction of another species, including metal and halogen displacement reactions, and combustion in both limited and excess oxygen environments	Oxidation and reduction	1.9%	6 of 6
4.2.2.2	structural formulae (condensed or showing bonds) can be used to show the arrangement of atoms and bonding in organic molecules that contain the following functional groups: alkenes, alcohols, aldehydes, ketones, carboxylic acids, esters, amines and amides	Properties and structure of organic materials	1.9%	6 of 6
4.2.2.19	the tertiary structure of a protein (the overall three-dimensional shape) is a result of folding due to interactions between the side chains of the $\alpha$ -amino acid in the polypeptide, including disulfide bridges, hydrogen bonding, dipole-dipole interactions, dispersion forces and ionic interactions	Properties and structure of organic materials	1.7%	6 of 6
4.2.2.4	IUPAC nomenclature is used to name organic species, including those with a parent chain of up to 8 carbon atoms with simple branching and one of the following functional groups: alkenes, alcohols, aldehydes, ketones, carboxylic acids, esters, amines and amides	Properties and structure of organic materials	1.7%	5 of 6
3.3.2.3	the relationship between acids and bases in equilibrium systems can be explained using the Brønsted-Lowry model and represented using chemical equations that illustrate the transfer of protons between conjugate acid-base pairs	Acids and bases	1.6%	6 of 6

These 20 dot points carry 59.3% of the paper marks between them. Another 54 assessed dot points share the rest, and 2 of the 76 externally assessable dot points have not been assessed in any of these 6 papers. Content that has not appeared is still examinable.

What has moved between papers

Comparing the 2020 to 2022 papers with the 2023 to 2025 papers, seven topics have moved by more than 3.0 percentage points.

Topic	2020 to 2022 share	2023 to 2025 share	Movement
Properties and structure of organic materials	30.0%	26.6%	down 3.4 points
Acids and bases	14.8%	19.7%	up 4.9 points
Chemical equilibrium systems	18.3%	14.8%	down 3.5 points
Oxidation and reduction	12.2%	17.2%	up 5.0 points
Chemical synthesis	11.0%	16.6%	up 5.6 points
Science Inquiry Skills (Unit 3)	10.3%	5.1%	down 5.2 points
Science Inquiry Skills (Unit 4)	3.4%	0.0%	down 3.4 points

How the papers are built

Short answer carries 63.8% of the marks across these 6 papers.

Question type	Share of marks	Marks	Parts
Short answer	63.8%	735	207
Extended response	23.2%	267	66
Multiple choice	13.0%	150	150

Verb	Share of marks	Marks	Parts
explain	13.1%	151	36
calculate	10.3%	119	23
write	8.8%	101	32
state	8.7%	100	36
determine	6.3%	73	11
identify	5.8%	67	23
justify	5.6%	65	17
describe	4.9%	57	14

What these percentages do not tell you

Where to practise

Every topic above links to its own page of real SCSA questions with marking criteria and average scores attached: Properties and structure of organic materials, Acids and bases, Chemical equilibrium systems, Oxidation and reduction, Chemical synthesis, Science Inquiry Skills (Unit 3) and Science Inquiry Skills (Unit 4). For how students actually score on this content, read WACE Chemistry hardest topics, and for the full question bank start at WACE Chemistry.

Syllabus and assessment material referenced in this guide is used under licence, © School Curriculum and Standards Authority. See our SCSA licensing notice. The School Curriculum and Standards Authority does not endorse this publication or product.