861 past contests
Topic 4 · Riddle: carbon monoxide
Topic 2 · Hydrogen bonding and relative boiling points (true/false)
Topic 7 · Balancing a redox equation: sum of coefficients
Topic 2 · Predicting an ionic formula from valence electron counts
Topic 6 · Solubility product from an evaporated residue mass
Topic 5 · Percentage composition, empirical and molecular formula
Topic 7 · Balancing half-reactions in acidic medium
Topic 14 · Riddle: chemical properties of matter
Topic 38 · Electrolytic versus galvanic cells (true/false)
Topic 15 · How reaction rate is (and is not) determined (true/false)
Topic 9 · Balancing equations: sum of coefficients
Topic 6 · Solubility product from dissolved ion concentration
Topic 14 · Riddle: thallium, a semiconductor-adjacent metal
Topic 3 · Acid strength, dilution and replaceable hydrogen (true/false)
Topic 37 · Definition of a binary compound (true/false)
Topic 5 · Mass of an element within a given mass of a hydrocarbon
Topic 10 · Enthalpy of reaction from enthalpies of formation
Topic 11 · Graham's law: molar mass from relative diffusion rate
Topic 12 · Mass required to neutralise a base or acid (1:1 reactions)