Effects of Greenhouse Gases
Section: 10. Chemistry of the Environment | Syllabus: Cambridge AS Level Physics 9702
Effects of Greenhouse Gases Greenhouse Gases Gases in the atmosphere that trap heat energy from the Sun, preventing it from escaping back into space. This causes the Earth's average temperature to rise, leading to global warming and climate change.
Main Greenhouse Gases Carbon dioxide (CO₂): From combustion of fossil fuels and deforestation Methane (CH₄): From agriculture (livestock), rice paddies, and decomposition in landfills Water vapor (H₂O): Natural component of the atmosphere How Greenhouse Gases Work The greenhouse effect mechanism: Short-wavelength radiation from the Sun passes through the atmosphere and reaches Earth's surface Earth's surface absorbs this energy and warms up Earth re-emits energy as long-wavelength infrared radiation Greenhouse gases in the atmosphere absorb this infrared radiation The trapped energy warms the atmosphere, raising global temperatures Global Warming The increase in Earth's average surface temperature caused by rising levels of greenhouse gases in the atmosphere.
This leads to climate change and various environmental consequences. Consequences of Global Warming Rising sea levels: Melting ice caps and thermal expansion of oceans Extreme weather: More frequent hurricanes, droughts, and floods Habitat loss: Species unable to adapt to rapid climate changes Ocean acidification: CO₂ dissolving in seawater, harming marine ecosystems Agricultural disruption: Changes in rainfall patterns and growing seasons Formation of Nitrogen Oxides Nitrogen oxides (NOₓ) are formed in car engines: At high temperatures in internal combustion engines, nitrogen and oxygen from air react N₂(g) + O₂(g) → 2NO(g) Nitrogen monoxide (NO) further oxidizes to nitrogen dioxide (NO₂) These gases contribute to acid rain and respiratory problems Catalytic Converters Catalytic converters reduce harmful emissions from car exhausts: Convert nitrogen oxides (NOₓ) back to harmless nitrogen gas (N₂) Convert carbon monoxide (CO) to carbon dioxide (CO₂) Oxidize unburned hydrocarbons to CO₂ and H₂O Use platinum, palladium, and rhodium as catalysts Key reactions in catalytic converters: 2CO + 2NO → 2CO₂ + N₂ 2CO + O₂ → 2CO₂
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