Sub-topic 1
2026 · National One-Eighth
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Mole-volume relationships: gas volume produced from mass of a hydrocarbon burned in combustion
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Sub-topic 3
2026 · National Preliminary
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Calculating moles from mass using molar mass, including hydrated salts
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Sub-topic 4
2026 · National Preliminary
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Relative atomic mass from isotopic abundance
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Sub-topic 5
2026 · National Preliminary
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Mass percent of water lost from a heated hydrated salt sample
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Sub-topic 6
2026 · National Preliminary
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Vapor pressure of a solution using raoult's law
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Sub-topic 7
2026 · National Preliminary
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Number of water molecules in a hydrate from a mass-equality condition
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Sub-topic 8
2026 · National Preliminary
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Number of atoms in a given mass of a molecular compound
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Sub-topic 9
2025 · National Preliminary
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Moles of co2 produced from complete combustion of a hydrocarbon
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Sub-topic 10
2025 · National Preliminary
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Mass of a compound from a given number of moles
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Sub-topic 11
2025 · National Preliminary
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Number of hydrogen atoms in a given mass of an organic compound
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Sub-topic 12
2026 · National Semifinal
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Relative atomic mass of a metal from the mass of its oxide
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Sub-topic 13
2026 · National Semifinal
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Maximum mass of ammonia formed with a limiting reagent
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Sub-topic 14
2025 · National Semifinal
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Mass of lead(ii) iodide precipitate from a double displacement reaction with potassium iodide
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Sub-topic 15
2025 · National Semifinal
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Minimum mass of oxygen required for a given mass of co2 in octane combustion
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Sub-topic 16
2025 · National Semifinal
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Percentage of an element within a fertilizer given the percentage of its oxide
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Sub-topic 17
2025 · National Semifinal
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Molar mass of a hydrated complex salt (potassium ferrocyanide trihydrate)
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Sub-topic 18
2024 · National Preliminary
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Molar mass of a hydrated complex salt
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Sub-topic 19
2026 · National Semifinal
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Mass of a carbonate heated to form a given mass of its oxide
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Sub-topic 20
2026 · National Quarterfinal
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Mass of oxide obtained from complete thermal decomposition of a carbonate
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Sub-topic 21
2026 · National Quarterfinal
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Total number of atoms in a given number of moles of a hydrocarbon
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Sub-topic 22
2026 · National Quarterfinal
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Identifying an element from the molar mass of a compound and a ratio of atomic masses
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Sub-topic 23
2026 · National Quarterfinal
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Average number of monomer units in a polymer chain from its average molecular mass
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Sub-topic 24
2018 · National Preliminary
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Temperature for a gas to reach a maximum volume at constant pressure
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Sub-topic 25
2025 · National Quarterfinal
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Mass of precipitate from a limiting-reagent double displacement
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Sub-topic 26
2025 · National Quarterfinal
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Remaining mass after a whole number of half-lives
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Sub-topic 27
2021 · National One-Eighth
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Finding an unknown atomic mass from a compound's molar mass
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Sub-topic 28
2026 · National Preliminary
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Finding an unknown atomic mass from a compound's mass and moles
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Sub-topic 29
2021 · National One-Eighth
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Combined molecule count after mixing two gas samples
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Sub-topic 30
2021 · National One-Eighth
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Maximum product mass from a limiting reagent
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Sub-topic 31
2021 · National Preliminary
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Number of atoms of an element in a given number of moles
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Sub-topic 32
2026 · National Preliminary
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Molar mass of a named ionic compound
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Sub-topic 33
2026 · National Final
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Mass of gas released from a fixed-volume cylinder at constant temperature
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Sub-topic 34
2023 · National Final
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Mass of sulfur dioxide released from the sulfur content of a fuel burned
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Sub-topic 35
2026 · National Preliminary
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Mass of co2 produced from complete combustion of a given mass of ethanol
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Sub-topic 36
2025 · National Preliminary
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Mass of aluminum produced from aluminum oxide and carbon (thermite-type reaction)
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Sub-topic 37
2024 · National Preliminary
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Predicting the products of a double displacement (metathesis) reaction
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Sub-topic 38
2023 · National Preliminary
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General properties of decomposition reactions (true/false)
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Sub-topic 39
2025 · National One-Eighth
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Chemical formula of an ionic compound from its name
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Sub-topic 40
2025 · National One-Eighth
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Total volume from combining several measured volumes of solution
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Sub-topic 41
2003 · National Semifinal
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Problem of the day: mass of a limiting-reagent product across a two-step synthesis with fractional yields
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Sub-topic 42
2003 · National Semifinal
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Number of molecules of a limiting-reagent product from moles of two gaseous reactants
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Sub-topic 43
2013 · National Semifinal
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Identity of soapless (synthetic) detergents
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Sub-topic 44
2014 · National Quarterfinal
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Mass of iron extractable from an ore given the ore's pyrite content
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Sub-topic 45
2014 · National Quarterfinal
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Riddle: carbon dioxide as a nonpolar triatomic molecule that sublimes readily
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Sub-topic 46
2016 · National One-Eighth
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Mass of silver from thermal decomposition of silver(i) oxide at a given efficiency
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Sub-topic 47
2016 · National One-Eighth
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Mass of silver(i) oxide needed to yield a given mass of silver (100% efficient)
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Sub-topic 48
2016 · National Preliminary
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Riddle: concentrated sulfuric acid, the most manufactured chemical
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Sub-topic 49
2018 · National Preliminary
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Volume of o2 needed to completely combust nonane
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Sub-topic 50
2018 · National Preliminary
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Volume of co2 released from complete combustion of heptane
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Sub-topic 51
2018 · National Preliminary
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Mass of water (steam) released from complete combustion of 2-methylbutane
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Sub-topic 52
2018 · National Preliminary
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Riddle: fritz haber, developer of the nitrogen-fixation (ammonia synthesis) process
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Sub-topic 53
2020 · National One-Eighth
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Avogadro's number/constant definition
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Sub-topic 54
2021 · National Preliminary
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Finding the atomic mass of b in ab2 from molar mass and a's atomic mass
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Sub-topic 55
2021 · National Preliminary
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Identifying cl2o5 as the chlorine oxide with a ~1:1 cl:o mass ratio
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Sub-topic 56
2021 · National Preliminary
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Mass of magnesium carbonate heated to form a given mass of magnesium oxide
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Sub-topic 57
2022 · National Preliminary
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Mass of water produced from combusting 8.80g of methane
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Sub-topic 58
2022 · National Preliminary
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Mass of co produced from incomplete combustion of 20.8g methane
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Sub-topic 59
2022 · National Preliminary
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Mass of co2 produced from combusting 16.8g of ethene
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Sub-topic 60
2023 · National Preliminary
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Problem of the day: verifying an antacid tablet's caco3 content against its label claim, via co2 evolved
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Sub-topic 61
2023 · National Preliminary
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Mass of carbon in a given mass of 2-hexene
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Sub-topic 62
2023 · National Preliminary
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Mass of a metal(ii) oxide from the metal's atomic mass, correcting the assumed m2o formula
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Sub-topic 63
2023 · National One-Eighth
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Moles of water formed from complete combustion of one mole of propane
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Sub-topic 64
2023 · National Quarterfinal
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Mass of molybdenum carbide formed from reacting a mass of moo2 with excess carbon
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Sub-topic 65
2023 · Regional Championship
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Moles of dichlorine heptoxide needed to produce a given amount of perchloric acid
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