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ago in Environmental Chemistry by (410 points)
How do changes in atmospheric concentrations of greenhouse gases contribute to global warming and what chemical reactions are involved in their formation and breakdown?

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ago by (470 points)
Changes in atmospheric concentrations of greenhouse gases contribute to global warming by trapping heat within the Earth's atmosphere. Greenhouse gases, such as carbon dioxide  CO2 , methane  CH4 , nitrous oxide  N2O , and water vapor  H2O , absorb and re-emit infrared radiation, which increases the temperature of the atmosphere. This process is known as the greenhouse effect.The chemical reactions involved in the formation and breakdown of greenhouse gases are as follows:1. Carbon dioxide  CO2 :Formation: The primary source of CO2 is the combustion of fossil fuels, such as coal, oil, and natural gas. The combustion reaction can be represented as:C_xH_y + O2  CO2 + H2OAnother significant source of CO2 is deforestation, which releases CO2 through the process of respiration and decomposition of organic matter.Breakdown: CO2 is removed from the atmosphere through natural processes such as photosynthesis, dissolution in water bodies, and chemical weathering of rocks. In photosynthesis, plants convert CO2 and water into glucose and oxygen:6CO2 + 6H2O + sunlight  C6H12O6 + 6O22. Methane  CH4 :Formation: Methane is primarily produced through anaerobic decomposition of organic matter, which occurs in wetlands, landfills, and the digestive systems of ruminant animals. The reaction can be represented as:C6H12O6  3CH4 + 3CO2Another source of methane is the extraction and combustion of fossil fuels, particularly natural gas.Breakdown: Methane is broken down in the atmosphere through a reaction with hydroxyl radicals  OH , which leads to the formation of CO2 and water:CH4 + 2OH  CO2 + 2H2O3. Nitrous oxide  N2O :Formation: Nitrous oxide is produced through microbial processes in soil and water, such as nitrification and denitrification. These processes involve the conversion of ammonia  NH3  to nitrate  NO3-  and the reduction of nitrate to nitrogen gas  N2 , respectively.Breakdown: Nitrous oxide is broken down in the atmosphere through photolysis and reactions with oxygen atoms  O  and hydroxyl radicals  OH , which result in the formation of nitrogen gas  N2  and nitric oxide  NO :N2O + O  N2 + O2N2O + OH  N2 + H2OBy understanding the chemical reactions involved in the formation and breakdown of greenhouse gases, we can develop strategies to reduce their emissions and mitigate the impacts of global warming. This can be achieved through the use of renewable energy sources, improved agricultural practices, and the development of technologies to capture and store CO2.
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