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Topic 1: Monitoring the Environment

7 dot points, in syllabus order. Each dot point has a focused answer, with exam-style questions and worked answers where available.

How do we monitor and explain the chemistry of air pollution?

Identify the major atmospheric pollutants, their sources, and the chemistry of photochemical smog formation.

Primary and secondary pollutants, the combustion sources of NOx, SOx, CO and particulates, and the radical photochemistry that produces ozone and smog, with worked SACE-style equation and concentration calculations.

8 min read →

How does molecular structure explain the greenhouse effect?

Explain the greenhouse effect in terms of the absorption of infrared radiation by greenhouse gas molecules.

Why greenhouse gases absorb infrared while N2 and O2 do not, the role of bond vibrations and dipole change, the enhanced greenhouse effect, and worked SACE-style emission and energy calculations.

8 min read →

How can the concentration of a metal ion be measured from the light it absorbs or emits?

Explain the principles of atomic absorption spectroscopy (AAS) and atomic emission spectroscopy, and their use in determining trace metal concentrations.

How AAS and atomic emission measure trace metals: electron transitions, element-specific wavelengths, the calibration-curve method and Beer-Lambert relationship, with worked SACE-style concentration-from-absorbance calculations.

9 min read →

How does chromatography separate and identify the components of a mixture?

Explain the principles of chromatography, including gas chromatography (GC) and high-performance liquid chromatography (HPLC), and interpret chromatograms.

Mobile and stationary phases, partitioning, retention time, and the difference between GC and HPLC, with worked SACE-style chromatogram interpretation and calibration calculations of component concentration.

9 min read →

How do chemists measure and judge the quality of water?

Describe the key indicators of water quality, including dissolved oxygen, BOD, pH, turbidity and ion concentrations.

Dissolved oxygen, BOD, pH, turbidity, hardness and ion concentrations as water-quality indicators, with the chemistry behind each measurement and worked SACE-style ppm and dissolved-oxygen calculations.

8 min read →

How can redox titrations measure the concentration of oxidising or reducing species in a sample?

Use redox titrations, including permanganate titrations, to determine the concentration of an analyte from balanced half-equations and stoichiometry.

Permanganate and iodine/thiosulfate redox titrations: combining half-equations to find the mole ratio, self-indicating endpoints, and fully worked SACE-style calculations from titre to analyte concentration.

9 min read →

How can we accurately measure the concentration of a solution?

Apply volumetric analysis using acid-base titrations to determine unknown concentrations.

Standard solutions, primary standards, titration technique, indicator choice and back-titration, with fully worked SACE-style stoichiometric calculations that take a titre back to an unknown concentration.

9 min read →