Chemistry

15 sections available · 43 chapters available

Free Chemistry revision notes for Senior Secondary (HKDSE) students. Each chapter covers a key topic with worked examples and practice prompts you can take straight into the thinka app.

Planet Earth

Atmosphere composition & testing O₂
Seawater composition, salt extraction, electrolysis, water isolation
Rocks & minerals, separation techniques: distillation, crystallization, filtration

Microscopic World I

Atomic structure, periodic trends
Ionic, covalent, metallic bonding, giant structures
Molecular shapes, formulae; link macro–micro

Metals

Metal ores, finite resource, recycling
Reactivity series, displacement, extraction methods
Corrosion, anodisation, social–environmental implications

Acids and Bases

Common acids/alkalis; H⁺(aq) concept; pH determination
Strong vs weak, dissociation extent
Titration techniques; volumetric analysis & stoichiometry

Fossil Fuels & Carbon Compounds

Sources: coal, petroleum, natural gas
Fractional distillation, uses, pollution effects
Homologous series; naming; addition polymerisation

Microscopic World II

Bond polarity by electronegativity
Intermolecular forces: Van der Waals’, hydrogen bonds
Molecular shapes (e.g. CH₄, NH₃, H₂O, BF₃)

Redox Reactions, Chemical Cells & Electrolysis

Oxidation numbers, redox reactions
Zinc–carbon cell, inert electrode cells, fuel cells
Electroplating, copper purification, environmental links

Chemical Reactions and Energy

Enthalpy changes; Hess’s Law; energy cycles
Stoichiometric calculations involving energy terms

Rate of Reaction

Reaction monitoring methods (titration, gas volume, temperature)
Instantaneous vs average rates; molar gas volumes
Collision theory, activation energy, catalysts

Chemical Equilibrium

Reversible reactions; dynamic equilibrium
Equilibrium constant (Kc); Le Chatelier’s Principle
Effects of temperature and concentration

Chemistry of Carbon Compounds

Homologous series (alkanes, alkenes, haloalkanes, alcohols, aldehydes, ketones, acids, esters, amides, amines)
Isomerism: structural, cis‑trans, enantiomerism
Reactions: substitution, addition, oxidation, esterification, hydrolysis; inter-conversions
Important compounds: aspirin, detergents, nylon, polyesters

Patterns in the Chemical World

Periodic trends: oxide acid-base character
Transition metals: coloured ions, variable oxidation states, catalysis

Industrial Chemistry

Kinetics, activation energy; Arrhenius equation
Catalysts; green chemistry (atom economy, pollution control)

Materials Chemistry

Natural polymers (cellulose, chitin)
Synthetic polymers; plastics, liquid crystals, nanomaterials
Comparison: metals vs alloys; composites

Analytical Chemistry

Cation tests (flame test), gas tests, purity tests
Volumetric (titration) quantitative analysis
Instrumental methods, forensic, environmental, clinical applications

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