9. Chemistry of the atmosphere Flashcards
Describe the earth’s early atmosphere and how it was formed?
- The earth was hot when it was formed
- there was significant volcanic activity
- gases have been released from these volcanoes
- these gases include carbon dioxide, nitrogen, methane, ammonia and water vapour
Describe the proportions of gases in the modern atmosphere
- around 80% nitrogen
- around 20% oxygen
- small quantities of carbon dioxide, water vapour and noble gases
How did the amount of oxygen in the atmosphere increase?
- Algae and plants produced the atmospheric oxygen by photosynthesis
- as the amount of oxygen gradually increased, there were more plants that produced more oxygen
How did the amount of carbon dioxide in the atmosphere decrease?
- when the oceans formed, carbon dioxide dissolved in the water and carbonates were precipitated producing sediment.
- some carbon dioxide was used in photosynthesis to make oxygen
What are greenhouse gases, give some examples?
- they are gases in the atmosphere that maintain temperatures on earth high enough to support life
- eg. methane, water vapour, carbon dioxide
What is the greenhouse effect?
- greenhouse gases allow short wavelength radiation from the sun to pass through the atmosphere to the earth’s surface,
- but absorb the outgoing long wavelength radiation from the earth, causing an increase in temperature
Why is the greenhouse effect necessary for life?
it is a natural phenomenon. without it, the earth would be too cold for life to exist
How have human activities led to an increase in greenhouse gases?
carbon dioxide - combustion and deforestation
methane - increased farming and decomposition in landfills
What are the potential effects of global climate change?
- Sea levels rise - which may cause flooding and increased coastal erosion
- more frequent and severe storms
- changes in the amount, timing and distribution of rainfall
- temperature and water stress for humans and wildlife
- changes in the food-producing capacity of some regions
- changes to the distribution of wildlife species
What is a carbon footprint?
The total amount of carbon dioxide and other greenhouse gases emitted over the full life cycle of a product, service or event
What actions can be taken to reduce a carbon footprint?
- increased use of alternative renewable energy supplies
- energy conservation
- carbon capture and storage
- carbon taxes and licenses
- carbon off-setting including through tree planting
- carbon neutrality - zero net release
What is carbon capture and storage?
where carbon dioxide is trapped in solvents and stored underground
What are the challenges faced with reducing a carbon footprint?
- scientific disagreement over causes and consequences of global climate change
- lack of public information and education
- lifestyle changes
- economic considerations
- incomplete international cooperation
What are the advantages of complete combustion?
- less soot is made
- more heat per gram of fuel is released
- poisonous carbon monoxide is not produced
What is soot?
carbon particles
