861 past contests
Topic 3 · Ph of a weak monoprotic acid solution from its molarity and pka
Topic 34 · Colours of common transition metal ions in aqueous solution
Topic 14 · Riddle: nickel
Topic 7 · Oxidation states of fluorine, alkali metals and metal hydrides (true/false)
Topic 2 · Basic concepts of ion formation and ionic crystals (true/false)
Topic 5 · Systematic name of a carbonyl compound from its molecular formula
Topic 2 · Enthalpy change of reaction from bond enthalpies (hess's law)
Topic 7 · Riddle: perchloric acid and chlorine's +7 oxidation state
Topic 2 · When hydrogen bonding does and doesn't occur (true/false)
Topic 2 · Requirements for covalent bond formation (true/false)
Topic 1 · Number of atoms of an element in a given number of moles
Topic 19 · Identifying a compound from a percentage mass ratio
Topic 9 · Balancing equations: sum of coefficients
Topic 5 · Empirical and molecular formula from mass/composition data
Topic 7 · Oxidation number of an unknown species in a compound
Topic 1 · Maximum product mass from a limiting reagent
Topic 1 · Combined molecule count after mixing two gas samples
Topic 6 · Constructing a balanced equation from an equilibrium expression
Topic 1 · Finding an unknown atomic mass from a compound's molar mass