SACE Stage 2 Chemistry deep dive: all four topics for the 2026 exam

How to use this deep dive

The SACE Stage 2 Chemistry exam can draw on all four topics. This guide follows the subject outline's subtopics and links every dot point on the site. A few site pages go beyond the Stage 2 outline; they are marked as background so you can prioritise. For format and exam technique, see the exam strategy guide.

Topic 1: Monitoring the environment

Global warming, ocean acidification and smog

Dot points: greenhouse gases and climate change, atmospheric pollutants and photochemical smog. Background: water quality indicators.

• Carbon dioxide and methane absorb and re-emit infrared radiation; extra anthropogenic greenhouse gases disrupt the atmosphere's thermal balance.
• Dissolved $\text{CO}_2$ lowers ocean pH through the carbonic acid equilibria, which reduces carbonate availability for shells.
• Nitrogen oxides form at high temperature in engines ($\text{N}_2 + \text{O}_2 \rightarrow 2\text{NO}$, then $2\text{NO} + \text{O}_2 \rightarrow 2\text{NO}_2$). Sunlight splits $\text{NO}_2$ ($\text{NO}_2 \rightarrow \text{NO} + \text{O}$), and the oxygen atom forms tropospheric ozone ($\text{O} + \text{O}_2 \rightarrow \text{O}_3$). Catalytic converters reduce NO to $\text{N}_2$.

Volumetric analysis

Dot points: volumetric analysis: acid-base titrations, redox titrations.

Know the units (mol L$^{-1}$, g L$^{-1}$, % w/v, ppm, ppb) and the procedure: rinse the burette and pipette with the solutions they will deliver, rinse the conical flask with distilled water only, and titrate to a consistent end-point, taking concordant titres.

Chromatography

Dot point: chromatography: GC and HPLC.

Components separate because they differ in the strength of their interactions with the stationary and mobile phases. On a polar stationary phase, more polar components are held more strongly and move more slowly.

Atomic spectroscopy

Dot point: atomic absorption and emission spectroscopy.

Electrons absorb specific energies to move to higher subshells and emit the same energies when they return, so each element has unique wavelengths. Write subshell configurations for the first 38 elements: calcium is $1s^2\,2s^2\,2p^6\,3s^2\,3p^6\,4s^2$ and $\text{Ca}^{2+}$ is $1s^2\,2s^2\,2p^6\,3s^2\,3p^6$.

Topic 2: Managing chemical processes

Dot points: reaction rates and collision theory, catalysts and activation energy, enthalpy and calorimetry, dynamic equilibrium and Kc, Le Châtelier's principle, the Haber process: rate versus yield, green chemistry principles.

• Rates: the slope of a concentration-time graph is the rate; it is steepest at the start. Higher concentration, pressure, temperature and surface area, or a catalyst, increase the rate through more frequent or more successful collisions.
• Energy profiles: show reactants, products, activation energy and $\Delta H$. A catalyst lowers the activation energy without changing $\Delta H$.
• Equilibrium: write Kc for homogeneous systems, calculate it from initial and equilibrium quantities, and predict shifts with Le Châtelier's principle. You may also be asked to deduce whether a reaction is exothermic from how the position changes with temperature.

Topic 3: Organic and biological chemistry

Dot points: hydrocarbons and IUPAC nomenclature, functional groups and isomerism, reactions of alkenes and haloalkanes, oxidation of alcohols, esterification and hydrolysis, addition and condensation polymers, biological molecules: proteins, carbohydrates and lipids, IR, mass spectrometry and NMR analysis.

The outline's subtopics run through the families in order: alcohols, aldehydes and ketones, carbohydrates, carboxylic acids, amines, esters, amides, triglycerides and proteins.

Topic 4: Managing resources

Energy

Dot points: fuels and enthalpy of combustion, redox reactions and oxidation numbers. Background for fuel cells: galvanic cells and electrode potentials, primary and secondary batteries.

• Complete combustion gives $\text{CO}_2$ and water; incomplete combustion (soot, CO) is more likely with longer chains.
• Compare fuels per mole, per gram and per litre. Ethanol releases about $1367 \div 46.07 \approx 29.7$ kJ g$^{-1}$, and with a density of 0.789 g mL$^{-1}$, about 23.4 MJ L$^{-1}$.
• Biofuels: bioethanol by fermentation and distillation; biodiesel by transesterification of triglycerides.
• Fuel cells are galvanic cells with a continuous supply of reactants. In a hydrogen fuel cell, hydrogen is oxidised at the negative anode and oxygen reduced at the positive cathode.

Water and soil

The outline's water and soil subtopics are covered here directly; this site does not yet have separate dot points for them.

• Water: aluminium ions and polymers flocculate negatively charged clay particles; zeolites soften hard water by exchanging $\text{Ca}^{2+}$ and $\text{Mg}^{2+}$ for $\text{Na}^+$; reverse osmosis forces water through a semi-permeable membrane; chlorine forms hypochlorous acid ($\text{Cl}_2 + \text{H}_2\text{O} \rightleftharpoons \text{HOCl} + \text{HCl}$), whose ionisation depends on pH.
• Soil: nitrogen, phosphorus and potassium are the major nutrients; cations on silicate surfaces exchange with soil water; high $\text{H}^+$ or $\text{Na}^+$ displaces nutrient cations; excess nitrogen and phosphorus cause eutrophication.

Materials

Dot points: electrolytic cells and electrolysis, extraction and corrosion of metals. Background: life cycle analysis and sustainability.

• Polymers: thermoplastics soften on heating and can be remoulded and recycled; thermosets are cross-linked and do not melt. More cross-linking gives more rigidity.
• Metals: the extraction method follows the activity series. Sodium is made by electrolysis of molten sodium chloride (sodium at the negative cathode, chlorine at the positive anode); zinc can be won by electrolysis of an aqueous solution.
• Recycling and composites: composites combine materials for better properties but are hard to separate and recycle.

Common mistakes

Check your knowledge

1. Write the subshell configuration of potassium. (Answer: $1s^2\,2s^2\,2p^6\,3s^2\,3p^6\,4s^1$.)
2. What is produced at the cathode in the electrolysis of molten sodium chloride? (Answer: sodium metal.)
3. Name the link formed between two amino acids. (Answer: a peptide, or amide, link.)

Then try the topics quiz.