Year 12 Chemistry
Module 5, Equilibrium and Acid Reactions, from why some reactions never finish to calculating Keq and Ksp.
- Each week
- One 3-hour lesson · 30-minute break
- In person · St Leonards
- Weekly from Saturday 17 October, decide by Saturday 24 October · 10:00am or 2:00pm
- Online · live from home
- Weekly from Sunday 18 October, decide by Sunday 25 October · 10:00am or 2:00pm
- Price
- $1,000 instead of $1,500 for all 10 lessons, for the first 5 students to sign up. Try 2 lessons before you pay
The term price covers all 10 lessons, the first 2 included. Pay up front, after the first lesson or after the second; if the class is not right by then, there is nothing to pay.
The term, lesson by lesson
In person Saturday 17 October to Saturday 19 December, online Sunday 18 October to Sunday 20 December. Follows the NESA Chemistry Stage 6 Syllabus (2017), which the 2027 HSC examines, in the order most schools teach it.
The term at a glance
| Lesson | Topic | In person | Online |
|---|---|---|---|
| Lesson 1 | Static and dynamic equilibriumReversible reactions and dynamic equilibrium | Sat 17 Oct | Sun 18 Oct |
| Lesson 2 | Static and dynamic equilibriumWhy some reactions never reach equilibrium | Sat 24 Oct | Sun 25 Oct |
| Lesson 3 | Factors that affect equilibriumLe Chatelier’s principle | Sat 31 Oct | Sun 1 Nov |
| Lesson 4 | Factors that affect equilibriumReading equilibrium graphs | Sat 7 Nov | Sun 8 Nov |
| Lesson 5 | The equilibrium constantWriting and interpreting Keq | Sat 14 Nov | Sun 15 Nov |
| Lesson 6 | The equilibrium constantKeq calculations | Sat 21 Nov | Sun 22 Nov |
| Lesson 7 | The equilibrium constantMeasuring Keq in the laboratory | Sat 28 Nov | Sun 29 Nov |
| Lesson 8 | Solution equilibriaDissolving and precipitation | Sat 5 Dec | Sun 6 Dec |
| Lesson 9 | Solution equilibriaThe solubility product, Ksp | Sat 12 Dec | Sun 13 Dec |
| Lesson 10 | Term reviewConsolidation and term test | Sat 19 Dec | Sun 20 Dec |
Static and dynamic equilibrium
Reversible reactions and dynamic equilibrium
- Module 5
- Static and Dynamic Equilibrium
- Open and closed systems, and static compared with dynamic equilibrium
- What is happening to reaction rates when a system reaches equilibrium
- Practical investigations: hydrating cobalt(II) chloride and the iron(III) thiocyanate equilibrium, contrasted with burning magnesium
Key skill: Sketching and reading concentration and rate graphs for a system reaching equilibrium.
Why some reactions never reach equilibrium
- Module 5
- Static and Dynamic Equilibrium
- Enthalpy and entropy, and Gibbs free energy: ΔG = ΔH − TΔS
- Combustion and photosynthesis as reactions that are not in equilibrium
- How activation energy and the heat of reaction relate to reversibility
Key skill: Calculating ΔG and using its sign to decide whether a reaction is spontaneous.
Factors that affect equilibrium
Le Chatelier’s principle
- Module 5
- Factors that Affect Equilibrium
- How changes in concentration, pressure, volume and temperature shift an equilibrium
- Explaining each shift with collision theory
- Practical investigations: the NO₂ and N₂O₄ system, adding ions to iron(III) thiocyanate, and heating cobalt chloride
Key skill: Predicting the direction of a shift and justifying it in a full written answer.
Reading equilibrium graphs
- Module 5
- Factors that Affect Equilibrium
- Identifying the change made to a system from a concentration against time graph
- Why a catalyst speeds up both reactions but does not move the equilibrium
- Balancing yield against rate in industrial processes
Key skill: Interpreting unfamiliar graphs in HSC-style questions.
The equilibrium constant
Writing and interpreting Keq
- Module 5
- Calculating the Equilibrium Constant
- Writing the equilibrium expression for reactions in solution and in the gas phase
- What a large or small Keq says about the position of equilibrium
- Comparing the reaction quotient Q with Keq to predict which way a reaction goes
- Why temperature is the only factor that changes Keq
Key skill: Writing Keq expressions and reasoning with Q against Keq.
Keq calculations
- Module 5
- Calculating the Equilibrium Constant
- Setting up ICE tables from initial amounts
- Calculating Keq from equilibrium data
- Finding an unknown equilibrium concentration from Keq
Key skill: Working through a multi-step ICE table calculation without losing the stoichiometry.
Measuring Keq in the laboratory
- Module 5
- Calculating the Equilibrium Constant
- Practical investigation: finding Keq for iron(III) thiocyanate by colorimetry
- Building and using a calibration curve
- Equilibrium constants for ionisation, introducing Ka for weak acids
Key skill: Using a calibration curve and identifying the main sources of error.
Solution equilibria
Dissolving and precipitation
- Module 5
- Solution Equilibria
- What happens to ionic compounds as they dissolve in water
- Practical investigation: using solubility rules to predict precipitates
- How Aboriginal and Torres Strait Islander Peoples remove toxins from foods such as cycad fruit
Key skill: Writing net ionic equations for precipitation reactions.
The solubility product, Ksp
- Module 5
- Solution Equilibria
- Writing Ksp expressions for sparingly soluble salts
- Calculating solubility from Ksp, and Ksp from solubility
- Predicting whether a precipitate forms when two solutions are mixed, allowing for dilution
Key skill: Multi-step Ksp calculations, including the dilution step students most often miss.
Term review
Consolidation and term test
- Module 5
- HSC-style multiple choice and extended response on equilibrium, Keq and Ksp, and solubility
- A short test under exam conditions, marked with written feedback
- A plan for the summer holidays, built around the titration and buffer work that opens Term 1
Key skill: Exam technique: setting out calculations so every step earns its mark.
How every lesson runs
3 hours of teaching with a 30-minute break, following the same pattern every week.
Check in
A short quiz on last week’s content, and the homework questions that caused trouble worked through on the board before anything new is taught.
Teach
The new content taught at the whiteboard, with worked examples that build from the first idea up to the standard of an HSC question.
Practise
Questions at four levels: Assimilate, Consolidate, Integrate and Extend. Everyone starts together and moves up as they are ready, with written work checked as they go.
Exam practice
Past HSC questions on the week’s topic, answered under time and marked against the NESA marking guidelines, so students learn what earns the marks.
Take home
Session notes and homework set at each student’s level, so the week’s work is secure before the next lesson builds on it.
What your child receives
Every student in the class gets all of this, week by week and across the term.
- Every week
A check-in quiz
A short quiz on last week’s content opens every lesson, so a gap is found and fixed before new work is built on top of it.
- Every week
Session notes
Notes on what the lesson covered, to revise from at home. They are sent even when a lesson is missed.
- Every week
Homework at their level
Questions set at one of four levels, Assimilate, Consolidate, Integrate or Extend, so the work stretches each student without losing them.
- Every week
Marked HSC questions
Past HSC questions on the week’s topic, answered under time and marked against the NESA marking guidelines.
- End of term
A term test with written feedback
A short test under exam conditions in the final lesson, marked and returned with written feedback on where the marks were won and lost.
- End of term
A holiday plan
A plan for the holidays that follow, built around the work that opens the next term.
The rest of Year 12
Where the course goes next, in the order schools teach it.
- Term 1, 2027
Module 6, Acid/Base Reactions: acid and base theories, pH calculations, titrations and buffers. Module 7, Organic Chemistry, usually begins late in the term.
- Term 2, 2027
Module 7: naming organic compounds, hydrocarbons, alcohols, organic acids and bases, and polymers. Module 8, Applying Chemical Ideas, begins.
- Term 3, 2027
Module 8 is completed: analysing inorganic and organic substances, and chemical synthesis. Then trial exams and revision for the HSC.
Questions about this class
Which syllabus does the Chemistry class follow?
The class follows the NESA Chemistry Stage 6 Syllabus (2017), which the 2027 HSC examines, in the order most schools teach it.
What if my school teaches Chemistry in a different order?
The class follows the plan on this page, which uses the order most schools teach Chemistry in. Where your school takes a topic earlier or later, that week’s lesson is either revision of work already done or a head start on what is coming. You keep the session notes from every lesson, so they are on hand when school reaches the topic.
Can I join partway through the term?
Yes. Classes run every week through the term, so you can start whenever suits and still have two lessons to decide before you pay. Tell us which course you are in and we will let you know what the class has covered so far.
What if I miss a week?
Tell us as early as you can. Where there is room, you can sit that week with the other day’s group. The Saturday and Sunday classes cover the same material and we will send the session notes either way.
Do I pay for the first two lessons?
Only if you stay. The term price covers every lesson, the first two included. Pay up front, after the first lesson or after the second. If the class is not right after two lessons, you pay nothing.
Sitting more than one?
Every course runs as its own class, each with its own plan.
Join the Chemistry class
Try 2 lessons before you pay. Tell us whether Saturdays in person or Sundays online suit, and we will confirm your session.