861 past contests
Topic 2 · Counting sigma and pi bonds in an alkyne
Topic 11 · Gas volume at stp from combustion stoichiometry
Topic 6 · Ionic product of a sparingly soluble hydroxide after mixing solutions
Topic 5 · Empirical formula atom count of a homologous series member
Topic 9 · Balancing equations: sum of coefficients
Topic 20 · Molar concentration from mass of dissolved ion
Topic 19 · Mass of an element present in a sample from its percentage composition by mass
Topic 2 · Total enthalpy of bonds formed in the product of a hydrogenation reaction from bond energies
Topic 6 · Equilibrium constant for dissociation of dinitrogen tetroxide from percentage dissociation
Topic 2 · Enthalpy change for combustion of a given mass from the molar enthalpy of combustion
Topic 12 · Volume of base needed to reach the second equivalence point titrating a diprotic acid
Topic 19 · Molecular formula of an oxide of nitrogen from percentage composition and molar mass
Topic 5 · Degree of unsaturation of an aromatic nitro compound
Topic 6 · Acid dissociation constant ka from the percentage ionization of a weak monoprotic acid
Topic 15 · Activity of a radioactive isotope remaining after a given number of half-lives
Topic 20 · Molar concentration of a concentrated acid from its density and mass percentage
Topic 1 · Identifying an element from the molar mass of a compound and a ratio of atomic masses
Topic 1 · Average number of monomer units in a polymer chain from its average molecular mass
Topic 6 · Solubility product of a hydroxide from the ph of its saturated solution
Topic 6 · Molar solubility of a hydroxide in a solution buffered at a fixed ph