Sub-topic 1
2026 · National One-Eighth
Free
Riddle: acid rain
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Sub-topic 2
2026 · National One-Eighth
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Mass of chlorine required for a water-treatment dose
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Sub-topic 3
2023 · National One-Eighth
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Converting ppm to percentage concentration
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Sub-topic 4
2023 · National One-Eighth
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The anomalous temperature of maximum water density
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Sub-topic 5
2021 · National Preliminary
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Riddle: carbon monoxide
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Sub-topic 6
2026 · National Preliminary
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Types of water-induced soil erosion
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Sub-topic 7
2024 · National One-Eighth
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Stages of the water treatment process
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Sub-topic 8
2023 · National Preliminary
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Riddle: water vapor, the most abundant greenhouse gas
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Sub-topic 9
2003 · National Semifinal
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Hydrofluorocarbons as cfc replacement refrigerants
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Sub-topic 10
2003 · National Semifinal
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Role of chlorofluoromethanes in stratospheric ozone depletion
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Sub-topic 11
2014 · National Final
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Increasing order of troposphere gas concentrations (co2, argon, o2, n2) (true/false)
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Sub-topic 12
2020 · National One-Eighth
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Carbon monoxide does not directly cause acid rain (true/false)
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Sub-topic 13
2020 · National One-Eighth
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A well-maintained engine can still emit acid-rain-causing gases (thermal nox) (true/false)
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Sub-topic 14
2020 · National One-Eighth
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Natural rainwater carbonic acid can dissolve limestone without human activity (true/false)
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Sub-topic 15
2023 · National Preliminary
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True or false: ozone gas can be detected by its odor
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Sub-topic 16
2023 · National Preliminary
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True or false: carbon monoxide gas can be detected by its odor
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Sub-topic 17
2023 · National Preliminary
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True or false: sulfur dioxide can be detected by its odor
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Sub-topic 18
2023 · National Quarterfinal
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Converting a co concentration from ppm to percentage
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