§-Module

Unit 3: Equilibrium, Acids and Bases, and Redox

19 dot points across 19 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

How do acid-base indicators change colour, and how do we choose the right indicator for a titration?

Explain how acid-base indicators work as weak acid equilibria and select an appropriate indicator for a titration

A focused answer to the WACE Year 12 Chemistry dot point on acid-base indicators, how they behave as weak acid equilibria, their colour change range, and how to choose an indicator matched to a titration equivalence point, with a worked example and common exam mistakes.

8 min answer →

What makes a substance an acid or a base, and how do we measure and calculate the pH of a solution?

Apply the Bronsted-Lowry theory, identify conjugate acid-base pairs, distinguish strong from weak acids and bases, and calculate pH using Kw

A focused answer to the WACE Year 12 Chemistry dot point on Bronsted-Lowry acids and bases, conjugate pairs, strong versus weak, Kw and pH calculations, with worked examples and common mistakes.

8 min answer →

How can a solution resist a change in pH when small amounts of acid or base are added?

Explain how buffer solutions resist changes in pH using Le Chatelier's principle and conjugate acid-base equilibria

A focused answer to the WACE Year 12 Chemistry dot point on buffers, how a conjugate acid-base mixture resists pH change, with the equilibrium reasoning, a worked example and common exam mistakes.

8 min answer →

How does a reversible reaction reach a dynamic equilibrium, and how does it respond when conditions change?

Explain dynamic chemical equilibrium and predict the effect of changes in concentration, pressure and temperature using Le Chatelier's principle

A focused answer to the WACE Year 12 Chemistry dot point on dynamic equilibrium and Le Chatelier's principle, with worked predictions and the most common exam mistakes.

7 min answer →

How are acids and bases linked in conjugate pairs, and how can one species act as both an acid and a base?

Identify conjugate acid-base pairs in proton-transfer reactions and explain amphiprotic behaviour

A focused answer to the WACE Year 12 Chemistry dot point on conjugate acid-base pairs, how they differ by one proton, the inverse strength relationship, and amphiprotic species, with a worked example and common exam mistakes.

7 min answer →

Why does iron rust, and how can we use electrochemistry to prevent it?

Explain the corrosion of iron as an electrochemical process and evaluate methods of corrosion prevention

A focused answer to the WACE Year 12 Chemistry dot point on corrosion, explaining rusting as an electrochemical process with anodic and cathodic regions, and evaluating prevention methods including sacrificial anodes and protective coatings, with a worked example and common exam mistakes.

8 min answer →

How can an external power source drive a non-spontaneous redox reaction in an electrolytic cell?

Describe the operation of electrolytic cells, predict the products of electrolysis, and explain industrial applications

A focused answer to the WACE Year 12 Chemistry dot point on electrolytic cells, how an external voltage drives non-spontaneous reactions, predicting products of molten and aqueous electrolysis, and industrial uses, with a worked example and common exam mistakes.

8 min answer →

What does the equilibrium constant tell us, and how do we calculate equilibrium concentrations?

Write equilibrium constant expressions, interpret their magnitude, and calculate equilibrium concentrations using an ICE table

A focused answer to the WACE Year 12 Chemistry dot point on Kc, the reaction quotient Q, and ICE-table calculations, with a fully worked numerical example and common errors.

9 min answer →

How does a galvanic cell convert the energy of a spontaneous redox reaction into electrical energy?

Describe the structure and operation of galvanic (voltaic) cells, including electrode reactions, electron and ion flow, and cell notation

A focused answer to the WACE Year 12 Chemistry dot point on galvanic cells, the roles of anode and cathode, electron and ion movement, the salt bridge, and cell notation, with a worked example and common exam mistakes.

7 min answer →

How do we track electron transfer and balance redox reactions using oxidation numbers and half-equations?

Assign oxidation numbers, identify oxidation and reduction, and balance redox half-equations and overall equations

A focused answer to the WACE Year 12 Chemistry dot point on oxidation numbers and half-equations, how to assign oxidation states, identify oxidation and reduction, and balance half-equations including in acidic solution, with a worked example and common exam mistakes.

8 min answer →

How do acids that can donate more than one proton ionise, and why does each successive ionisation get weaker?

Describe the stepwise ionisation of polyprotic acids and explain why successive ionisation constants decrease

A focused answer to the WACE Year 12 Chemistry dot point on polyprotic acids, their stepwise ionisation, why each successive Ka is smaller, and how this affects pH and titrations, with a worked example and common exam mistakes.

8 min answer →

How can we calculate the mass of substance produced at an electrode from the current and time of electrolysis?

Apply Faraday's laws to relate charge, current, time and the amount of substance produced or consumed at an electrode

A focused answer to the WACE Year 12 Chemistry dot point on quantitative electrolysis, using the relationships Q = It and Q = nF with the Faraday constant to calculate the amount of substance deposited or liberated at electrodes, with a worked example and common exam mistakes.

8 min answer →

How can we predict which way a reaction not yet at equilibrium will shift to reach equilibrium?

Calculate the reaction quotient Q and compare it with Kc to predict the direction in which a reaction will proceed to reach equilibrium

A focused answer to the WACE Year 12 Chemistry dot point on the reaction quotient, how Q is calculated and compared with Kc to predict the direction of net reaction, with a worked example and common exam mistakes.

8 min answer →

How is electron transfer used to generate electricity in galvanic cells and to drive reactions in electrolytic cells?

Assign oxidation numbers, write and balance half-equations, and use the standard electrode potential series to predict and calculate cell potentials for galvanic and electrolytic cells

A focused answer to the WACE Year 12 Chemistry dot point on oxidation numbers, half-equations, galvanic and electrolytic cells and standard electrode potentials, with a worked cell-potential calculation and common mistakes.

9 min answer →

Why does pure water conduct electricity slightly, and how does the ionic product of water link pH and pOH?

Explain the self-ionisation of water, define and use the ionic product Kw, and relate pH, pOH and temperature

A focused answer to the WACE Year 12 Chemistry dot point on the self-ionisation of water, defining the ionic product Kw, relating pH and pOH, and explaining the temperature dependence of Kw with a worked example and common exam mistakes.

8 min answer →

How does the equilibrium between a slightly soluble salt and its ions explain dissolving and precipitation?

Write solubility product expressions, calculate Ksp and solubility, and predict precipitation by comparing the ionic product with Ksp

A focused answer to the WACE Year 12 Chemistry dot point on solubility equilibria, covering the solubility product Ksp, how it links to molar solubility, the common ion effect, and predicting precipitation with worked examples and common exam mistakes.

8 min answer →

How does the standard electrode potential series let us predict whether a redox reaction will occur and how much voltage it produces?

Use the standard electrode potential series to predict the spontaneity of redox reactions and calculate standard cell potentials

A focused answer to the WACE Year 12 Chemistry dot point on standard electrode potentials, the reference hydrogen electrode, predicting spontaneity, and calculating standard cell EMF from the potential series, with a worked example and common exam mistakes.

8 min answer →

What is the difference between a strong and a weak acid, and how do Ka, Kb and pKa measure acid and base strength?

Distinguish strong from weak acids and bases by degree of ionisation, and define and use Ka, Kb and pKa to compare strengths

A focused answer to the WACE Year 12 Chemistry dot point on strong versus weak acids and bases, the acid and base ionisation constants Ka and Kb, the meaning of pKa, and how they quantify strength, with a worked example and common exam mistakes.

8 min answer →

How do we use titration to find an unknown concentration, and what shape does a titration curve take?

Perform and interpret acid-base titrations, sketch titration curves, and calculate unknown concentrations from volumetric data

A focused answer to the WACE Year 12 Chemistry dot point on volumetric analysis, the technique and calculations of acid-base titration, the shape of titration curves for different acid-base combinations, and the equivalence point, with a worked example and common exam mistakes.

8 min answer →