Chemistry of the atmosphere

• How long ago did Earth's atmosphere begin to form?

  4500 million years ago
• What gases were present in Earth's early atmosphere due to volcanic activity?

  Carbon dioxide (CO₂), water vapour (H₂O), and nitrogen (N₂)
• What happened to water vapour as Earth cooled down?

  Water vapour condensed to form oceans
• How did carbon dioxide levels change as oceans formed?

  Some carbon dioxide dissolved into the oceans, lowering its amount in the atmosphere
• What organisms produced the first oxygen through photosynthesis?

  Cyanobacteria and green algae
• What was the effect of photosynthesis on carbon dioxide and oxygen levels?

  CO₂ decreased and O₂ increased
• What did the shells and skeletons of marine life form over time?

  They formed sedimentary rocks made of calcium carbonate
• What is the current composition of Earth's atmosphere?

  79% nitrogen, 20% oxygen, and 0.04% carbon dioxide
• What are the two main ways carbon dioxide is removed from the atmosphere?

  • Photosynthesis
  • Dissolved in oceans
• What happens to carbon dioxide when it dissolves in oceans?

  It reacts with metal oxides to form metal carbonates
• What is produced when fossil fuels are burned?

  Carbon dioxide and water
• What is the difference between complete and incomplete combustion?

  Complete combustion has a plentiful oxygen supply, while incomplete combustion has a limited oxygen supply
• What is a major problem with carbon monoxide?

  It is toxic, odorless, and colorless
• How can the problems caused by carbon monoxide be reduced?

  By ensuring a good supply of oxygen during combustion
• What is the greenhouse effect?

  It is the warming of the Earth's atmosphere due to greenhouse gases absorbing and re-radiating thermal radiation
• What are the main greenhouse gases?

  Carbon dioxide (CO₂), methane (CH₄), and water (H₂O)
• What human activities increase carbon dioxide levels in the atmosphere?

  Burning fossil fuels and deforestation
• What are the effects of global climate change?

  Flooding, extreme weather events, and changes in rainfall
• What are the consequences of increased global temperatures?

  • Melting polar ice caps
  • Rising sea levels
  • Flooding of land
  • Coastal erosion and habitat loss
• What is the role of peer review in scientific research?

  It checks that research is scientifically accurate before publication
• What is the main cause of acid rain?

  Sulfur dioxide reacting with rainwater
• How can the problems caused by sulfur dioxide be reduced?

  By removing sulfur dioxide from waste gases before they reach the atmosphere
• What is the effect of nitrogen oxides on human health?

  They can trigger asthma and cause respiratory problems
• How can nitrogen oxides be reduced in car emissions?

  By using catalytic converters to convert them into nitrogen
• What is the impact of soot on the atmosphere?

  Soot causes pollution and contributes to global warming
• What is the problem with unburnt hydrocarbons in the atmosphere?

  They waste fuel and are considered greenhouse gases
• How does carbon monoxide affect the blood?

  It combines irreversibly with hemoglobin, reducing oxygen transport
• What are the main sources of methane emissions?

  • Cattle production
  • Landfill decay of waste
• What has been the trend in carbon dioxide levels since 1900?

  The rate of increase in CO₂ has been rising due to burning fossil fuels
• What are the consequences of rapid climate change on biodiversity?

  Animals and plants may not adapt quickly enough and could die out
• What happens to the Earth's temperature as carbon dioxide levels increase?

  The temperature increases
• What is the greenhouse effect's role in supporting life on Earth?

  It keeps the Earth warm enough to support life
• What is the significance of the peer-review process in scientific research?

  It ensures the accuracy and reliability of research findings
• What are the effects of acid rain on the environment?

  It can damage plants, stonework, and increase acidity in water bodies
• How does the combustion of fossil fuels contribute to climate change?

  It releases carbon dioxide, a greenhouse gas, into the atmosphere
• What is the role of water vapor in the atmosphere?

  It is a greenhouse gas but human activity does not significantly affect its levels
• What is the impact of human activities on the levels of greenhouse gases?

  Human activities increase the levels of greenhouse gases, contributing to global warming
• What are the consequences of increased flooding due to climate change?

  It leads to coastal erosion and habitat loss
• How does climate change affect weather patterns?

  It causes more extreme weather events
• What happens to rainfall patterns as climate changes?

  Changes in how much rain falls, when it occurs, and where it occurs