Chemistry ATAR Year 12 syllabus — effective January 2024
School assessment comprises Science inquiry 20%, Extended response 10%, Test 20% and Examination 50%. The external ATAR course examination has 10 minutes reading time and 180 minutes working time. The 2025 reference paper has 203 raw marks: Section One, 25 multiple-choice questions for 25 marks; Section Two, nine short-answer questions for 65 marks; Section Three, six extended questions for 113 marks. The section weightings are 25%, 35% and 40% respectively, so the raw mark total is not the percentage weighting. The original practice papers retain 203 total raw marks while varying section allocations and question counts according to their individual practice plans; the section percentage weightings remain distinct from raw marks. The examination mark and moderated school mark contribute equally to the combined mark. The Chemistry Data booklet is supplied; a separate formula sheet is not supplied. Approved equipment and current arrangements should be checked against the official front cover.
Past papers on this subject span more than one syllabus. Papers written under an older one still work as practice, but the units and content areas they test have changed — the index labels every paper with the syllabus it was set under.
Syllabus effective January 2024 · 2024–presentEarlier syllabus — check current alignment · 2020–2023
The units and content areas, one by one
Each area below lists the concepts named in the syllabus, what the SCSA exam asks of them, and the mistake that most often costs marks.
- Unit 3 — Chemical equilibrium systems
- Unit 3 — Acids and bases
- Unit 3 — Oxidation and reduction
- Unit 4 — Properties and structure of organic materials
- Unit 4 — Chemical synthesis
Area 1 of 5
Unit 3 — Chemical equilibrium systems
Explain reaction rates through collision frequency, activation energy and orientation. Distinguish an open system from a closed one and constant equilibrium composition from stopped reaction. Use energy profiles, equilibrium expressions and Le Châtelier reasoning to predict responses to temperature, concentration and gas-volume changes, including carbonate chemistry in seawater.
What the syllabus lists under this area · 4 points
- Collision theory and the factors affecting reaction rate
- Open and closed systems, reversibility and dynamic equilibrium
- Le Châtelier's Principle: temperature, concentration, pressure, volume and catalysts
- Equilibrium law expressions, the equilibrium constant and energy profile diagrams
What the exam asks
Questions can ask for particle-level explanations, equilibrium expressions, predictions and interpretation of rate or concentration graphs. Connect each prediction to the stated disturbance and balanced equation; temperature can change K, while a catalyst changes the rate of approach to equilibrium.
Where marks go missing
Equal forward and reverse rates do not imply equal concentrations. Count gaseous stoichiometric coefficients before predicting a pressure effect, and distinguish inert gas added at fixed volume from expansion at fixed pressure.
Area 2 of 5
Unit 3 — Acids and bases
Use proton-transfer equations to identify conjugate pairs, amphiprotic species and salt hydrolysis. Separate acid strength from concentration, interpret Ka qualitatively, and calculate strong-acid or strong-base pH using Kw at 25 °C. Explain buffers, indicators and titration procedures through the chemistry they rely on.
What the syllabus lists under this area · 4 points
- Brønsted-Lowry acids and bases, conjugate pairs, acid strength and Ka
- Kw, [H+], [OH-] and pH calculations
- Salt hydrolysis and buffer solutions
- Acid-base indicators, titrations and volumetric calculations
What the exam asks
Show the reacting mole ratio in volumetric calculations and justify indicator choice from the pH change around equivalence. Practical reasoning includes glassware conditioning, uncertainty and the distinction between repeatable measurements and a systematically biased result.
Where marks go missing
The observed indicator end point is not the definition of equivalence, and equivalence is not always pH 7. Do not substitute a weak acid’s analytical concentration directly for its equilibrium hydrogen-ion concentration.
Area 3 of 5
Unit 3 — Oxidation and reduction
Track electron transfer through oxidation numbers and balanced half-equations in acidic conditions. Use standard electrode potentials to compare reaction tendencies and calculate standard cell voltage. Explain galvanic and electrolytic cells, electron flow, ionic conduction, copper refining, silver plating and corrosion prevention.
What the syllabus lists under this area · 3 points
- Oxidation numbers, half-equations and redox equations in acidic conditions
- Galvanic cells, standard electrode potentials and cell voltage
- Electrolytic cells, electrorefining, electroplating and corrosion of iron
What the exam asks
A complete cell explanation identifies the actual electrode reactions, electrode signs, direction of electron flow and role of the electrolyte or salt bridge. Relate a proposed protective metal or plating arrangement to the required oxidation and reduction processes.
Where marks go missing
Oxidation is always at the anode, but electrode signs differ between galvanic and electrolytic cells. Electrons do not travel through a salt bridge, and tabulated electrode potentials are not multiplied when balancing half-equations.
Area 4 of 5
Unit 4 — Properties and structure of organic materials
Recognise and name the listed functional groups in simple structures with parent chains up to eight carbons. Distinguish chain, position and cis–trans isomers; predict alkene addition, alcohol oxidation and esterification. Link intermolecular forces to properties, calculate empirical and molecular formulae, and interpret polymer and protein structures.
What the syllabus lists under this area · 6 points
- Functional groups, structural formulae and IUPAC naming
- Chain, position and cis-trans isomerism
- Addition, alcohol oxidation, esterification and functional-group tests
- Intermolecular forces, boiling point, solubility and empirical/molecular formulae
- Addition and condensation polymers: monomers and repeating units
- α-Amino acids, zwitterions, peptide bonds and protein structure
What the exam asks
Use structural evidence and chemical observations together when identifying an unknown. Show valid bonds and retained side groups in repeat units, recover appropriate monomers, and distinguish peptide sequence from the interactions stabilising higher levels of protein structure.
Where marks go missing
A molecular formula can describe several isomers. Breaking intermolecular attractions during boiling is different from breaking covalent bonds, and a molecule can accept hydrogen bonds from water without being able to donate them itself.
Area 5 of 5
Unit 4 — Chemical synthesis
Plan connected reaction steps, determine limiting reagents and calculate theoretical and percentage yields. Evaluate the rate–yield compromises in the Haber and Contact processes, ethanol production and biodiesel synthesis. Explain saponification, cleaning in hard water, and how polymer structure affects material properties and uses.
What the syllabus lists under this area · 3 points
- Designing a synthesis: reaction sequences, limiting reagent and percentage yield
- Haber process, Contact process, biodiesel and ethanol: optimising rate and yield
- Saponification, soaps and detergents, and the structure and uses of plastics
What the exam asks
Extended scenarios can combine equations, quantitative data and evaluation of process conditions. Show how each reagent and condition achieves the required transformation, and assess sustainability using the stated energy, feedstock, waste and separation information.
Where marks go missing
A high isolated yield does not establish that a process uses little energy or produces little waste. Soap formation and biodiesel transesterification produce different fatty-acid derivatives; do not interchange their products or equations.
Common questions
Are these real SCSA examination questions?
No. The practice questions and marking explanations are original ATARMAxxing resources aligned to the course specification. Official papers and ratified marking keys are linked separately, and the platform is not affiliated with SCSA.
Why do the practice papers have 203 marks rather than 100?
The 2025 reference paper has 25, 65 and 113 raw section marks. SCSA weights those sections at 25%, 35% and 40%. Raw marks and percentage contribution are different quantities; historical raw totals can vary.
Is Chemistry a 190-minute writing examination?
No. The reference instructions allow 10 minutes reading plus 180 minutes working. A displayed total of 190 minutes includes reading time; it does not add ten minutes of writing.
Which organic chemistry skills are in scope?
The syllabus specifies its listed functional groups, simple IUPAC structures up to eight carbons, isomerism, characteristic reactions, physical properties, formula determination, polymers and proteins. Advanced reaction mechanisms and IR or NMR analysis are not required substitutes for those specified skills.
How should I use papers from before 2024?
They were set under the earlier syllabus version. Check each question against the current syllabus before using it for targeted revision, and use the official marking key rather than assuming every historical raw mark total is identical.