Chemistry of the atmosphere

• What is the proportion of nitrogen in the modern atmosphere?

  Around 80%
• What is the proportion of oxygen in the modern atmosphere?

  Around 20%
• What gases are present in small quantities in the modern atmosphere?

  CO2, H2O, and noble gases
• What was the state of the Earth when it was formed?

  • The Earth was hot
  • There was significant volcanic activity
  • Gases were released from volcanoes
  • Gases included CO2, N2, CH4, NH3, H2O
• How did the amount of oxygen in the atmosphere increase?

  Through photosynthesis by algae and plants
• What is the photosynthesis equation that produces oxygen?

  6 CO2 + 6 H2O → C6H12O6 + 6 O2
• How did the amount of carbon dioxide in the atmosphere decrease?

  • CO2 dissolved in oceans, forming carbonates
  • Used in photosynthesis to produce oxygen
• What is the greenhouse effect?

  It maintains Earth's temperatures for life
• Why is the greenhouse effect necessary for life?

  It prevents Earth from being too cold
• How have human activities increased greenhouse gases?

  • Carbon dioxide: combustion and deforestation
  • Methane: increased farming and landfill decomposition
• What are the potential effects of global climate change?

  • Sea level rise and flooding
  • More frequent and severe storms
  • Changes in rainfall distribution
  • Temperature and water stress
  • Changes in food production capacity
  • Changes in wildlife distribution
• What is a carbon footprint?

  Total greenhouse gases emitted over a lifecycle
• What actions can reduce a carbon footprint?

  • Use alternative energy supplies
  • Energy conservation
  • Carbon capture and storage
  • Carbon taxes and licenses
  • Carbon offsetting through tree planting
  • Achieve carbon neutrality
• What challenges are faced in reducing a carbon footprint?

  • Scientific disagreement on climate change
  • Lack of public information and education
  • Resistance to lifestyle changes
  • Economic considerations
  • Incomplete international cooperation
• What are the advantages of complete combustion?

  • Less soot produced
  • More heat released per gram of fuel
  • No poisonous carbon monoxide produced
• How is pollution caused by combustion?

  Gases like CO2 and SO2 are released
• What issues are associated with sulfur dioxide and oxides of nitrogen?

  • Cause respiratory problems in humans
  • Contribute to acid rain
  • Damage plants and buildings
• What problems do particulates cause?

  • Cause global dimming
  • Reduce sunlight reaching Earth
  • Health problems due to lung damage