HKDSE Chemistry: twelve compulsory topics, three electives of which you take two, and free practice questions

Which topics does HKDSE Chemistry cover?

Fifteen in total: twelve compulsory and three electives. The compulsory part starts with the substances around you and works inwards to atoms, bonding, energy and rate, then out again to equilibrium and the patterns of the periodic table. The electives each take one strand further, and a school normally enters its candidates for two of the three.

• Planet Earth: the atmosphere, the ocean, rocks and minerals
• Microscopic World I: atomic structure, the periodic table, metallic, ionic and covalent bonding, and how structure decides properties
• Metals: occurrence and extraction, the reactivity series, reacting masses, corrosion and its prevention
• Acids and Bases: acids and alkalis, indicators and pH, strong against weak, salts and neutralisation, concentration, volumetric analysis
• Fossil Fuels and Carbon Compounds: hydrocarbons from fossil fuels, homologous series and naming, alkanes and alkenes, addition polymers
• Microscopic World II: bond and molecular polarity, intermolecular forces, the structure of ice, non-octet structures, the shapes of simple molecules
• Redox Reactions, Chemical Cells and Electrolysis: everyday chemical cells, the reactions inside them, oxidation and reduction, electrolysis
• Chemical Reactions and Energy: energy changes in reactions, standard enthalpy change, Hess's law
• Rate of Reaction: measuring rate, the factors that change it, the molar volume of a gas at room temperature and pressure
• Chemical Equilibrium: dynamic equilibrium, the equilibrium constant, the effect of concentration and temperature on position
• Chemistry of Carbon Compounds: named homologous series, isomerism, the typical reactions of each functional group, interconversion, important organic substances
• Patterns in the Chemical World: periodic variation from Li to Ar, the oxides of Na to Cl, the general properties of transition metals
• Industrial Chemistry (elective): the importance of industrial processes, rate equations, activation energy, catalysis, green chemistry
• Materials Chemistry (elective): natural and synthetic polymers, plastics, metals and alloys, modern synthetic materials, green chemistry
• Analytical Chemistry (elective): detecting chemical species, separation and purification, quantitative analysis, instrumental methods, what analytical chemistry contributes to society

Do you have to choose which electives to revise?

Your school chooses, and you revise the two you are entered for. A revision bank that carries only one pairing is a gamble, because a change of school or of the school's pairing strands half the elective material. Ours carries all three electives alongside all twelve compulsory topics, so the choice never has to be made at the point of buying, and the free questions below sample every one of the fifteen.

Why does this page not state the paper structure, the timings or the marks?

Because we have not verified them against a current official document, and a wrong number here would defeat the purpose of the page. In particular, the assessment framework fixes the weighting of Paper 1 Section A but not a question count, so any count you see quoted is almost certainly one year's actual paper being passed off as a rule. The topic framework is stable and publicly documented, so that is what this page states. For paper structure, timings, marks and the assessment framework, go to the HKEAA and to your school.

What actually catches Chemistry candidates out?

Terminology across two languages, and pairs of concepts that sit one word apart. A student who learned the idea in Chinese still has to name it in English: 置換 is displacement, 沉澱 is precipitation, 電離 is ionisation, 焓變 is enthalpy change, 活性序 is the reactivity series. The second trap is the near-miss definition, and multiple-choice is built to find it.

• Strong and concentrated: how completely an acid ionises against how much of it is in the solution
• Dynamic equilibrium and no reaction: equal forward and backward rates against nothing happening
• Enthalpy change and activation energy: the difference between the levels against the barrier between them
• Oxidation and gaining oxygen: loss of electrons is the definition that survives every case
• Empirical and molecular formula: the simplest whole-number ratio against the actual count in one molecule

Where do these questions come from?

They are original. Every question, option, explanation, flashcard and topic note is written by RiverMap Learning to the topic framework in the publicly available Chemistry Curriculum and Assessment Guide (Secondary 4 to 6), 2007, updated June 2018. No HKEAA past paper question, marking scheme or textbook content is reproduced. Scientific facts are not copyrightable, and the published framework is used only to align coverage. Each item is checked by a second AI model from a different family, which also confirms that equations balance, disagreements are settled by hand, and Chinese terminology is checked against the usage in Hong Kong textbooks.

Is RiverMap Learning connected to the HKEAA or the EDB?

No. RiverMap Learning is not affiliated with, endorsed by or sponsored by the Hong Kong Examinations and Assessment Authority, the Education Bureau, the Curriculum Development Council or any school. These pages and the app are independent revision material. The app reports how well you are doing on its own practice questions; that is not a grade, and HKDSE levels are awarded by standards-referenced reporting each year rather than by a fixed mark.