Chemistry: should I choose it?

Properties and Structure of Matter

Introduction to Quantitative Chemistry

Reactive Chemistry

Drivers of Reactions

Module 5: Equilibrium and Acid Reactions

This module builds the idea that many reactions never finish. You distinguish static equilibrium from dynamic equilibrium, where forward and reverse reactions continue at equal rates, and use Le Chatelier's principle to predict how a system shifts when concentration, temperature, pressure or volume changes — and why a catalyst changes none of that, only the time taken to get there. The treatment then turns numerical: writing the equilibrium expression, calculating the equilibrium constant from equilibrium concentrations, using the solubility product to predict whether a precipitate forms, and interpreting what a very large or very small constant says about the extent of reaction. Acid and base dissociation are applications of equilibrium constants here. Brønsted–Lowry models, pH and titration are developed in Module 6.

Module 6: Acid/Base Reactions

Module 6 separates two ideas students routinely merge: concentration and strength. A strong acid ionises completely in water while a weak acid sets up an equilibrium, so a dilute strong acid can have a lower pH than a concentrated weak one. You also distinguish monoprotic acids from polyprotic acids, which donate more than one proton and therefore titrate in stages. Brønsted–Lowry theory is used to explain behaviour rather than simply to label it — identifying which species donates the proton, which accepts it, what the conjugates are, and which species are amphiprotic. The quantitative strand is titration: matching an indicator's transition range to the pH at equivalence, reading the shape of a titration curve for each combination of strong and weak reagents, and locating the equivalence point. Applications cover neutralisation in industry, agriculture and the body. Quantitative work also includes pH and pOH, dilution and mixing calculations, Ka and pKa, and preparing buffers and explaining their role in natural systems.

Module 7: Organic Chemistry

Organic chemistry is a systems module: almost every mark depends on naming and drawing structures correctly. You learn IUPAC nomenclature for hydrocarbons and for compounds carrying functional groups — haloalkanes, alcohols, aldehydes, ketones, carboxylic acids, esters, amines and amides — including how to number a chain and order substituents. Hydrocarbon chemistry contrasts the saturated alkanes, which undergo substitution, with unsaturated alkenes and alkynes, which undergo addition across the double or triple bond. Reactions of organic compounds then link the families together: oxidation of primary alcohols through to carboxylic acids, esterification under acid catalysis, and the physical property trends in boiling point, solubility and flammability that follow from intermolecular forces. The module ends with polymers, distinguishing addition polymerisation of monomers containing a double bond from condensation polymerisation, which eliminates a small molecule.

Module 8: Applying Chemical Ideas

The final module asks how a chemist works out what a substance actually is. Inorganic analysis covers qualitative tests — flame tests, precipitation reactions and the systematic identification of cations and anions — alongside quantitative methods including gravimetric analysis, titration, and instrumental techniques such as atomic absorption spectroscopy and colourimetry with calibration curves. Organic analysis introduces chromatography, mass spectrometry for molecular mass and fragmentation, infrared spectroscopy for functional groups, and proton and carbon-13 NMR, which are used together to deduce an unknown structure from a set of spectra. Chemical synthesis and design reverses the problem: given a target molecule, plan a route to it, and evaluate an industrial process against yield, energy input, availability of reagents and the principles of green chemistry, including atom economy and waste minimisation.