SACE Chemistry exam 2026Exam: Wed 4 Nov · SACE Board timetable

A primary pollutant is released directly into the atmosphere from a source. A secondary pollutant is not emitted directly but forms in the atmosphere from chemical reactions of primary pollutants, often driven by sunlight.

Use GC for small, volatile, heat-stable molecules; use HPLC for large, non-volatile or heat-sensitive ones. The deciding factor is whether the analyte can be vaporised intact. Both rely on the same partitioning principle and both quantify by peak area against a calibration curve.

where $n$ is amount in $\text{mol}$, $c$ is concentration in $\text{mol L}^{-1}$, and $V$ is volume in $\text{litres}$. Always convert $\text{mL}$ to $\text{L}$ (divide by $1000$) before substituting.

A catalyst is a substance that increases the rate of a reaction by providing an alternative reaction pathway with a lower activation energy, without being consumed in the overall reaction. It may take part in intermediate steps but is regenerated, so its amount is unchanged at the end.

If a system at equilibrium is subjected to a change in concentration, pressure, volume or temperature, the position of equilibrium shifts in the direction that partly counteracts the change. The system never fully cancels the disturbance; it moves to a new equilibrium that reduces its effect.

A functional group is a specific atom or group of atoms within a molecule that is responsible for its characteristic chemical reactions. Molecules with the same functional group behave similarly, so functional groups let us organise the millions of organic compounds into a small number of reactive families.

When numbering a chain, give the lowest locant first to the principal functional group or multiple bond, then to substituents. For a simple branched alkane with no double bond, number from whichever end gives the substituents the lowest set of numbers. This single rule resolves most naming ambiguities.

Hydrogenation: $\text{H}_2$ adds with a nickel (or platinum) catalyst to give an alkane. $\text{CH}_2=\text{CH}_2 + \text{H}_2 \rightarrow \text{CH}_3\text{CH}_3$.

$Q$ is charge in coulombs ($\text{C}$), $I$ current in amperes ($\text{A}$), $t$ time in seconds, and $F$ the Faraday constant ($96500\ \text{C mol}^{-1}$, the charge of one mole of electrons). The half-equation then gives the mole ratio between electrons and product.