Topic C9-chemistry of the atmosphere

• What is the current composition of the Earth's atmosphere?

  78% nitrogen, 21% oxygen
• Why has the Earth's atmosphere changed over time?

  Due to natural processes and biological activity
• What process led to the increase of oxygen levels in the atmosphere?

  Photosynthesis by plants and algae
• How did carbon dioxide levels decrease over time?

  Through oceans dissolving gas and photosynthesis
• What is the chemical equation for photosynthesis?

  6CO2 + 6H2O → C6H12O6 + 6O2
• What role do algae and plants play in the atmosphere?

  They produce oxygen and consume carbon dioxide
• What are the main gases in the current atmosphere?

  Nitrogen, oxygen, argon, carbon dioxide
• How does carbon dioxide get locked up in rocks?

  Through formation of limestone and fossil fuels
• What is coal made from?

  Remains of dead plants
• How are oil and natural gas formed?

  From remains of dead marine organisms
• What happens to the remains of marine organisms over time?

  They become covered in mud and turn to rock
• What is limestone composed of?

  Calcium carbonate from marine organisms' shells
• How does carbon dioxide return to the atmosphere?

  Through volcanic eruptions and burning fossil fuels
• What are the effects of deforestation on carbon dioxide levels?

  It increases carbon dioxide in the atmosphere
• What are the stages of Earth's atmosphere since its formation?

  1. Initial atmosphere from volcanic eruptions
  2. Development of oxygen-rich atmosphere due to photosynthesis
  3. Current atmosphere with stable nitrogen and oxygen levels
• How did volcanoes contribute to the formation of the Earth's atmosphere?

  • Released gases like carbon dioxide and water vapor
  • Created a primordial atmosphere
  • Set the stage for later biological processes
• How did the level of oxygen change through time?

  It increased due to photosynthesis
• How was carbon dioxide removed from the early atmosphere?

  Through photosynthesis and ocean absorption