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Difficulty: MediumGreenhouse Effect, Global Warming, and Ozone Layer Depletion

Match each atmospheric phenomenon or chemical process on the left with its precise molecular mechanism or cause on the right.

  • Tropospheric thermal radiation trappingVibrational absorption and re-emission of outgoing terrestrial infrared radiation by gases like CO2\text{CO}_2 and CH4\text{CH}_4
  • Stratospheric ozone catalytic destructionPropagation cycle initiated by free radicals where Cl+O3→ClO+O2\text{Cl} + \text{O}_3 \rightarrow \text{ClO} + \text{O}_2
  • Chlorofluorocarbon (CFC) photolysisHomolytic cleavage of carbon-chlorine bonds induced by high-energy solar ultraviolet light
  • Natural stratospheric ozone layer formationSolar UV decomposition of O2\text{O}_2 into atomic oxygen followed by reaction with diatomic oxygen

Answer

Tropospheric thermal radiation trapping matches vibrational absorption of terrestrial infrared radiation; Stratospheric ozone catalytic destruction matches the chlorine radical propagation reaction cycle; Chlorofluorocarbon (CFC) photolysis matches homolytic cleavage of carbon-chlorine bonds by ultraviolet light; Natural stratospheric ozone layer formation matches solar UV decomposition of O2\text{O}_2 into atomic oxygen followed by reaction with O2\text{O}_2.
Each atmospheric process is accurately paired with its chemical mechanism: tropospheric heat trapping is driven by infrared absorption by greenhouse gases; stratospheric ozone catalytic breakdown occurs through free-radical propagation steps involving atomic chlorine; CFC photolysis involves solar UV cleavage of C-Cl bonds; and natural ozone formation requires UV dissociation of diatomic oxygen into atomic oxygen.

Step-by-Step Solution

1
Analyze the process of tropospheric thermal radiation trapping
Identify that global warming / greenhouse effect involves absorption and re-emission of terrestrial infrared (heat) radiation by gases like CO2\text{CO}_2 and CH4\text{CH}_4.
Greenhouse gases selectively interact with outgoing longwave thermal radiation in the troposphere.
2
Analyze stratospheric ozone depletion and CFC reactions
Distinguish between CFC photolysis (UV cleavage of C-Cl bonds releasing Cl radicals) and the catalytic propagation cycle (Cl+O3→ClO+O2\text{Cl} + \text{O}_3 \rightarrow \text{ClO} + \text{O}_2).
Photolysis produces reactive radicals, whereas propagation steps directly decompose ozone repeatedly.
3
Analyze the formation mechanism of the ozone layer
Identify that natural stratospheric ozone is created when UV light dissociates O2\text{O}_2 into oxygen atoms, which combine with O2\text{O}_2 to form O3\text{O}_3.
This dynamic photochemical cycle maintains the ozone shield in the stratosphere.

Key Concept

Greenhouse Effect, Global Warming, and Ozone Layer Depletion
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Topics

Greenhouse Effect, Global Warming, and Ozone Layer Depletion

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