Year 12 · Unit 3
WACE Chemistry, Year 12 (Unit 3)
Unit 3 Chemistry moves into equilibrium — reactions that don't go to completion but settle into a dynamic balance — and this reframing trips up students who spent Year 11 assuming every reaction runs to completion. Le Chatelier's principle, acid-base equilibria and pH calculations, and electrochemistry (galvanic cells, electrolysis) round out the unit, all building on Unit 1 and 2's bonding and stoichiometry foundations. Note: this page currently covers Unit 3 only — Unit 4 content isn't yet in our dataset, so treat this as a partial picture of the full Year 12 course.
Unit 3
Equilibrium, acid-base calculations and electrochemistry.
Chemical equilibrium
Explaining dynamic equilibrium as a state where forward and reverse reactions continue at equal rates.
Where students get stuck: Assuming equilibrium means the reaction has stopped. It hasn't — both the forward and reverse reactions are still happening, just at matched rates, so the concentrations stay constant rather than the reaction itself being over. This distinction underpins everything else in the unit.
Le Chatelier's principle
Predicting how an equilibrium system responds to a change in conditions using Le Chatelier's principle.
The equilibrium constant (Kc)
Calculating and interpreting the equilibrium constant for a reaction.
Acid-base equilibria, Ka and pH
Calculating pH and using Ka to compare the strength of weak acids.
Titration curves and buffers
Interpreting titration curves and explaining how buffer solutions resist pH change.
Oxidation and reduction (redox)
Assigning oxidation numbers and identifying oxidation and reduction in a reaction.
Galvanic cells and electrode potentials
Explaining how galvanic cells generate electricity and using standard electrode potentials to predict reactions.
Electrolysis
Explaining electrolysis and its industrial applications.
Redox titrations and corrosion
Applying redox chemistry to titrations, corrosion and electrochemical cell problems.
How it is assessed
- Unit 3 and Unit 4 combine school assessment, moderated by SCSA, with an external written examination set by SCSA at the end of the year.
- The combined school and examination result is what contributes to the ATAR for this course.
- A course must be completed to at least a C grade average across Units 3 and 4 for the result to count toward the WACE.
Common questions
- Has this syllabus changed recently?
- WACE senior secondary syllabuses are reviewed by SCSA on a rolling basis rather than all at once — there's no single blanket revision date the way there is for the P-10 curriculum. Check senior-secondary.scsa.wa.edu.au for the current syllabus version of this specific course before relying on unit content for assessment planning.
- Why does this page only cover Unit 3?
- It's a genuine gap in our current content, not a claim that Unit 4 doesn't exist. Unit 4 (typically organic chemistry) is part of the real Year 12 Chemistry course — we just haven't written that portion yet.
- What's the biggest conceptual shift from Year 11 into Unit 3?
- Accepting that not every reaction goes to completion. Year 11 stoichiometry treats reactions as running until a reactant runs out; equilibrium chemistry in Unit 3 is built around reactions that reach a stable balance instead, and a lot of early Unit 3 confusion traces back to still thinking in Year 11 terms.
Related year levels
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Start learning for freeWritten from the current WACE course syllabus. Requirements change — check SCSA for the official syllabus.