100+ Free Cameroon GCE O-Level Chemistry Practice Questions

Matter, Atomic Structure & Chemical Bonding

Kinetic particle theory of solids, liquids, and gases, state changes, diffusion rates, criteria of purity (fixed melting and boiling points), separation techniques (filtration, simple distillation, fractional distillation, separating funnel, paper chromatography, crystallization), atomic structure (protons, neutrons, electrons), atomic number ($Z$), mass number ($A$), isotopes, relative atomic mass, Bohr electronic configurations ($2,8,8,...$), ionic bonding (electrostatic attraction between oppositely charged ions in giant lattice), covalent bonding (shared pairs of electrons in simple molecules and giant structures), and metallic bonding (lattice of positive ions in a sea of delocalized electrons).

Stoichiometry, Chemical Formulae & Equations

Chemical valencies, radicals, writing and balancing chemical equations, state symbols, the mole concept, Avogadro's constant ($N_A = 6.02 \times 10^{23}\text{ mol}^{-1}$), molar mass ($M_r$), percentage composition by mass, determination of empirical and molecular formulae from combustion and mass data, stoichiometric calculations of reacting masses, percentage yield and purity, molar gas volume ($24\text{ dm}^3\text{ mol}^{-1}$ at room temperature and pressure), concentration of solutions in $\text{g/dm}^3$ and $\text{mol/dm}^3$, and volumetric acid-base titrations.

Acids, Bases, Salts & Qualitative Analysis

Properties and definitions of acids and bases, the pH scale, universal indicator and litmus/methyl orange/phenolphthalein, strong versus weak acids (mineral acids vs organic acids), classification of oxides (acidic, basic, amphoteric, neutral), neutralization reactions, methods of salt preparation (acid + metal, acid + insoluble base, acid + carbonate, acid + alkali titration, precipitation of insoluble salts), qualitative testing for aqueous cations ($Cu^{2+}$, $Fe^{2+}$, $Fe^{3+}$, $Al^{3+}$, $Zn^{2+}$, $Ca^{2+}$, $NH_4^+$) using aqueous sodium hydroxide and aqueous ammonia, flame tests, anion tests ($Cl^-$, $Br^-$, $I^-$, $SO_4^{2-}$, $CO_3^{2-}$, $NO_3^-$), and gas identification ($H_2$, $O_2$, $CO_2$, $Cl_2$, $NH_3$, $SO_2$).

Periodicity, Metals & Reactivity Series

Periodic Table organization by atomic number, periodic trends across periods and down groups, Group 1 alkali metals (reactions with water and oxygen, trend in reactivity), Group 7 halogens (physical states, displacement reactions, reactivity trend), Group 0 noble gases, the reactivity series of metals ($K, Na, Ca, Mg, Al, Zn, Fe, Pb, H, Cu, Ag, Au$), displacement reactions of metals and metal oxides, metallurgy and extraction of iron in the blast furnace (reactions, slag formation, reducing agent $CO$), extraction of aluminium by electrolysis of molten bauxite in cryolite, corrosion and rust prevention (painting, greasing, galvanizing, sacrificial protection), and redox reactions defined in terms of oxygen gain/loss, electron transfer (OIL RIG), and oxidation number changes.

Organic Chemistry, Energetics & Reaction Rates

Homologous series characteristics, functional groups, IUPAC nomenclature, isomerism, alkanes (combustion, substitution with chlorine in UV light), alkenes (addition of hydrogen, bromine water test for unsaturation, hydration to alcohols), fractional distillation of crude oil and catalytic cracking, alcohols (fermentation of glucose, combustion, oxidation to carboxylic acids), carboxylic acids (reactions with metals, bases, and carbonates, esterification with alcohols), polymers (addition polymerization of ethene/propene, condensation polymerization of nylon/terylene, environmental impacts of plastics), thermochemistry (exothermic vs endothermic reactions, $\Delta H$, energy profile diagrams, bond breaking and bond making), and factors affecting reaction rates (temperature, concentration/pressure, particle size/surface area, catalysts) explained through collision theory and activation energy.