Lesson 3.3.3.3

3.3.3.3 Ozone depletion Quiz: AQA Chemistry, Unit 3

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 3.3.3.3, Ozone depletion: 20 multiple choice questions for the AQA Chemistry (7405), Unit 3: Organic chemistry, written with Revision Ninja.

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The 20 questions

  1. What harmful radiation does atmospheric ozone absorb to protect life on Earth?

    • Infrared radiation
    • Microwave radiation
    • Gamma radiation
    • Ultraviolet radiation

  2. What bond in CFCs is broken by ultraviolet radiation to form chlorine atoms?

    • C-F only
    • C-H
    • C-Cl
    • O-O

  3. What role do chlorine free radicals play in the decomposition of stratospheric ozone?

    • Initiator
    • Inhibitor
    • Catalyst
    • Reactant

  4. Which equation shows the first step of the chlorine catalysed decomposition of ozone?

    • ClO + O2 -> Cl + O3
    • Cl + O3 -> ClO + O2
    • Cl + O2 -> ClO2
    • O3 + O3 -> 2O2 + O2

  5. Which equation shows the second step regenerating chlorine atoms in ozone decomposition?

    • ClO + O2 -> Cl + O3
    • Cl + O2 -> ClO2
    • ClO + O3 -> 2O2 + Cl
    • ClO + ClO -> Cl2 + O2

  6. What is the overall equation for the chlorine-catalysed decomposition of ozone?

    • 2O3 -> 3O2
    • Cl2 + O3 -> ClO2 + O
    • O3 + O2 -> O4
    • O3 -> O2 + O

  7. What is the common name of the group of compounds responsible for the chlorine atoms in ozone depletion?

    • Chlorofluorocarbons (CFCs)
    • Polyalkenes
    • Alcohols
    • Carboxylic acids

  8. Which property made chlorofluorocarbons suitable for use as refrigerants and aerosol propellants?

    • Corrosive nature
    • Low reactivity
    • High flammability
    • High solubility

  9. What key element do modern replacements for chlorofluorocarbons lack?

    • Chlorine
    • Fluorine
    • Carbon
    • Hydrogen

  10. What evidence persuaded governments to introduce legislation banning chlorofluorocarbons?

    • Ozone depletion research
    • Ocean acidification studies
    • Acid rain data
    • Global warming models

  11. Why can a single chlorine radical destroy thousands of ozone molecules?

    • It is regenerated
    • It is consumed
    • It absorbs photon
    • It forms polymers

  12. Which wavelength range of radiation is absorbed by ozone in the upper atmosphere?

    • Radio waves
    • Ultraviolet
    • Infrared only
    • Gamma rays only

  13. What term describes a region of the upper atmosphere with a reduced concentration of ozone?

    • Ozone depletion
    • Greenhouse effect
    • Photochemical smog
    • Thermal inversion

  14. Which equation shows that O3 decomposes to O2 and an oxygen atom?

    • O2 -> 2O
    • O3 -> O2 + O
    • O3 -> 2O2
    • O3 + O -> O4

  15. What is the oxidation state of chlorine in ClO?

    • +2
    • +1
    • -1
    • 0

  16. Which of these compounds is a chlorine-free replacement for CFCs?

    • Hydrofluorocarbons (HFCs)
    • Chloromethane
    • Dichlorodifluoromethane
    • Carbon tetrachloride

  17. Which species is primarily responsible for catalysing the breakdown of ozone in the stratosphere?

    • Alkene molecules
    • Nitrate ions
    • Chlorine radicals
    • Hydroxide ions

  18. Why do chlorofluorocarbons persist long enough in the atmosphere to reach the stratosphere?

    • Low boiling point
    • High chemical stability
    • Large molar mass
    • High water solubility

  19. Why are small amounts of chlorine radicals able to cause widespread ozone destruction?

    • Exothermic radical decay
    • Rapid termination steps
    • High radical mass
    • Catalytic cycle regeneration

  20. What was required to convince governments to enact legislation banning chlorofluorocarbons?

    • Economic forecasts
    • Corporate sponsorship
    • Public opinion polls
    • Peer-reviewed research

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