chemistry of the atmosphere

• How long ago did the Earth form?

  1. 4.6 billion years
• Why is it hard to gather evidence about the Earth's early atmosphere?

  Because it is from a long time ago
• What was the first phase of the Earth's atmospheric evolution?

  • Phase 1: Volcanoes released gases
  • Surface covered in erupting volcanoes
  • Early atmosphere formed from volcanic gases
• What gas was the early atmosphere mostly composed of?

  Carbon dioxide
• How does the early atmosphere compare to Mars and Venus today?

  It was similar to their atmospheres
• What other gases were released by volcanic activity?

  Nitrogen, water vapour, methane, ammonia
• What happened when water vapour in the atmosphere condensed?

  • It formed the oceans
  • Carbon dioxide dissolved in oceans
  • Carbonate precipitates formed sediments
• What process did green plants and algae use to absorb carbon dioxide?

  Photosynthesis
• What did marine animals' shells and skeletons contain?

  Carbonates from the oceans
• What happens to carbon after organisms die?

  • They fall to the seabed
  • Get buried by sediment layers
  • Form sedimentary rocks, oil, and gas
• What are fossil fuels made from?

  Plants, plankton, and marine animals
• What is coal made from?

  Thick plant deposits
• What is limestone primarily made of?

  Calcium carbonate deposits
• What is the process of photosynthesis in plants?

  • Converts carbon dioxide and water into sugars
  • Uses light energy
  • Produces oxygen as a byproduct
• When did algae evolve?

  About 2.7 billion years ago
• What is the chemical equation for photosynthesis?

  6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
• What happened as oxygen levels built up in the atmosphere?

  More complex life could evolve
• What is the current composition of the atmosphere?

  • Approximately 80% nitrogen
  • Approximately 20% oxygen
  • Small amounts of other gases
• What are the small amounts of other gases in the atmosphere?

  Mainly carbon dioxide, noble gases, water vapour
• What is the role of greenhouse gases in the Earth's atmosphere?

  They act as an insulating layer.
• How do greenhouse gases contribute to the greenhouse effect?

  They absorb long wavelength radiation and re-radiate it.
• Which gases are considered greenhouse gases?

  Carbon dioxide, methane, and water vapour.
• What happens to long wavelength radiation in the greenhouse effect?

  It gets re-radiated in all directions.
• How does deforestation affect greenhouse gas levels?

  It reduces CO₂ removal via photosynthesis.
• What is the impact of burning fossil fuels on greenhouse gases?

  It releases CO₂ that was previously stored.
• How does agriculture contribute to greenhouse gas emissions?

  Farm animals produce more methane.
• What is the effect of growing waste on greenhouse gases?

  It increases CO₂ and methane from decomposition.
• What recent trend has been observed in the Earth's temperature?

  The average temperature has been increasing.
• What do most scientists agree about the increase in carbon dioxide?

  It is causing the increase in Earth's temperature.
• Why is it difficult to understand the Earth's climate?

  It is complex with many variables.
• What has led to speculation about climate change in the media?

  Stories may be biased or incomplete.
• What are the potential consequences of climate change?

  • Melting polar ice caps and rising sea levels
  • Changes in rainfall patterns affecting water supply
  • Increased frequency and severity of storms
  • Impact on wild species distribution
• How could an increase in global temperature affect polar ice caps?

  It could lead to melting and rising sea levels.
• What might changes in rainfall patterns cause?

  Some regions may get too much or too little water.
• How might climate change affect food production?

  It may affect regions' ability to produce food.
• What is a potential effect of climate change on storms?

  The frequency and severity of storms may increase.
• How can changes in temperature and water availability affect wild species?

  It may lead to differences in their distribution.
• What is causing climate change according to the text?

  Greenhouse gas emissions from human activities
• Why is it useful to know what leads to carbon dioxide emissions?

  To slow down climate change
• What do carbon footprints measure?

  Greenhouse gases released over a life cycle