VCE Chemistry SACs: how they work and how to prepare
Half of your VCE Chemistry study score is decided before you ever sit the end-of-year exam. The School-assessed Coursework (SAC) you complete in Units 3 and 4 is worth 50 per cent of your result, the exam is the other 50 per cent. That makes SACs worth understanding properly, yet most students go into their first one unsure what it even is.
The good news is that the format is set out in the VCAA Chemistry Study Design and does not change from school to school. The task types are prescribed, the marks are fixed, and the conditions are known in advance. This guide covers what a SAC actually is, how much each one is worth, what the Unit 3 and Unit 4 SACs cover, the four task types your teacher chooses from, the Unit 4 scientific poster, and how to prepare.
What a SAC actually is
SAC stands for School-assessed Coursework. Unlike the exam, which is written and marked by the VCAA, your SACs are set and marked by your own school, using task types and mark allocations prescribed by the study design.
The defining conditions, straight from the study design, are that SAC tasks:
- are part of the regular teaching and learning program,
- are completed mainly in class and within a limited timeframe, and
- must not unduly add to your workload outside that program.
In other words, a SAC is an in-class assessment done under set conditions during the normal course, not a take-home assignment you grind on for weeks.
One important point about which SACs count. You do coursework in Units 1 and 2 as well, but only Units 3 and 4 contribute to your study score. Units 1 and 2 are assessed by your school as satisfactory or not satisfactory for each outcome. When people talk about "the SACs that matter," they mean the Unit 3 and Unit 4 ones.
How much each SAC is worth
Your study score is built from three components:
| Component | Contribution to study score |
|---|---|
| Unit 3 School-assessed Coursework | 20 per cent |
| Unit 4 School-assessed Coursework | 30 per cent |
| End-of-year examination | 50 per cent |
Notice that Unit 4 coursework (30 per cent) carries more weight than Unit 3 (20 per cent), and that the two units of coursework together (50 per cent) match the exam exactly. SACs are not a warm-up for the real thing, they are half the real thing.
What the Unit 3 SACs cover
Unit 3 is "How can design and innovation help to optimise chemical processes?" Your level of achievement is assessed across its two outcomes, each worth 40 marks (80 marks total for the unit's coursework):
- Outcome 1 (40 marks) sits in Area of Study 1, What are the current and future options for supplying energy? You compare fuels quantitatively (combustion products and energy outputs), apply the electrochemical series to design, construct and test primary cells and fuel cells, and evaluate the sustainability of electrochemical cells.
- Outcome 2 (40 marks) sits in Area of Study 2, How can the rate and yield of chemical reactions be optimised? You analyse chemical systems to predict how rate and extent can be optimised (collision theory, Le Chatelier's principle, the equilibrium constant Kc and reaction quotient Q), explain electrolysis, and evaluate the sustainability of electrolytic processes.
What the Unit 4 SACs cover
Unit 4 is "How are carbon-based compounds designed for purpose?" It has three outcomes, each worth 40 marks (120 marks total):
- Outcome 1 (40 marks), Area of Study 1, How are organic compounds categorised and synthesised? Structures, naming, properties and reactions of organic families, and designing reaction pathways for synthesis.
- Outcome 2 (40 marks), Area of Study 2, How are organic compounds analysed and used? Qualitative and quantitative analysis, deducing structures from instrumental data (MS, IR, ¹H and ¹³C NMR, chromatography), and how some medicines function.
- Outcome 3 (40 marks), Area of Study 3, the student-designed scientific investigation, assessed as a scientific poster (covered in its own section below).
The four task types your teacher picks from
For each of Outcomes 1 and 2 in both units (four outcomes in total), your teacher selects one task from this prescribed menu of four forms:
- Comparison and evaluation of chemical concepts, methodologies and methods, and findings from at least two practical activities.
- Analysis and evaluation of primary and/or secondary data, including identified assumptions or data limitations, and conclusions.
- Problem-solving, including calculations, using chemistry concepts and skills applied to real-world contexts.
- Analysis and evaluation of a chemical innovation, research study, case study, socio-scientific issue, or media communication.
Three rules govern how these are used:
- Each task type can be selected only once across Units 3 and 4. With four outcomes drawing on four task types, you will meet each form exactly once over the year, so you cannot dodge a style you find hard.
- At least one of the four tasks should reference sustainability (green chemistry runs through the whole study design).
- The time allocated for each is approximately 50 to 70 minutes for a written response, or about 10 minutes for a multimodal or oral presentation.
The practical takeaway: do not just revise content, get comfortable with all four task styles, because one of them is coming whether you like it or not.
The Unit 4 scientific poster
Unit 4 Outcome 3 (40 marks) is different from every other SAC. It assesses a student-designed and student-conducted scientific investigation that generates your own primary data, related to producing energy or chemicals, or analysing or synthesising organic compounds. (The investigation can be run in Unit 3 or Unit 4, or across both, but it is always assessed in Unit 4.)
You present it as a scientific poster built to a structure set out in the study design, with a few hard rules:
- The poster must not exceed 600 words.
- A one-sentence summary of your major finding sits in the centre and occupies 20 to 25 per cent of the poster space.
- You keep a logbook throughout, used for recording, assessment and authentication of your work.
This is the closest VCE Chemistry gets to genuine research, so the marks reward a clear question, sound method, honest analysis of error and uncertainty, and a conclusion that actually answers your aim.
Why your exam still affects your SACs
One thing students often miss: your raw SAC scores are not your final SAC scores. The VCAA statistically moderates each school's SAC results against that school's performance on the common end-of-year exam, so that coursework is comparable across every school in the state. Practically, that means doing well in the exam lifts the value of your SAC ranking, and the exam and your SACs are not separate worlds. Strong, consistent work across both is what pays off.
How to prepare for SACs
- Practise under timed, in-class conditions. A SAC is 50 to 70 minutes, so train at that pace, not in open-ended study sessions.
- Drill all four task types. Especially the data-analysis and evaluation forms, where marks are lost on weak conclusions and ignored limitations rather than wrong chemistry.
- Build the key science skills. Analysing primary and secondary data, identifying error and uncertainty, and evaluating methods are assessed again and again.
- Keep a genuine logbook for the poster. Record as you go, not the night before, because it is your authentication and the backbone of the investigation.
- Use the VCAA Data Book all year. It is meant to be part of teaching and learning, not just reserved for the exam, so knowing your way around it is a year-long advantage.
- Match your response to the command word and the marks. An "evaluate" is not a "describe", and a high-mark question is not a one-liner.
The fastest way to improve is fast, specific feedback on practice responses, because the bottleneck is rarely finding content, it is finding out whether your answer actually earned the marks.
That is where an interactive tutor helps. Avocado is an AI-powered Chemistry tutor built specifically for the VCE study design, so you can drill Unit 3 and Unit 4 outcomes, attempt data-analysis and evaluation responses, and get specific feedback on exactly where you lost marks before each SAC.
Frequently asked questions
What does SAC stand for? School-assessed Coursework. It is assessment set and marked by your school, completed mainly in class under set conditions, using task types prescribed by the VCAA Chemistry Study Design.
How much are SACs worth in VCE Chemistry? Unit 3 coursework is worth 20 per cent of your study score and Unit 4 coursework is worth 30 per cent, so SACs total 50 per cent. The end-of-year exam is the other 50 per cent.
Do Units 1 and 2 SACs count towards my study score? No. Units 1 and 2 are assessed by your school as satisfactory or not satisfactory for each outcome. Only Unit 3 and Unit 4 coursework contributes to the study score.
How many SACs are there? Across Units 3 and 4 you are assessed on five outcomes: Unit 3 has two, Unit 4 has three (the third being the scientific poster investigation). How these are packaged into sittings is decided by your school.
What are the four SAC task types? A comparison and evaluation of findings from at least two practicals; an analysis and evaluation of data with conclusions; a problem-solving task with calculations in a real-world context; and an analysis and evaluation of an innovation, study, issue or media communication. Each is used once across Units 3 and 4.
What is the scientific poster? The Unit 4 Outcome 3 assessment: a student-designed investigation presented on a poster of no more than 600 words, with a one-sentence central finding and a supporting logbook.
Assessment details sourced from the VCE Chemistry Study Design (Units 3 and 4: 2024–2027) and the VCAA support materials. Always confirm current conditions with your teacher and the VCAA website.