9. Chemistry of the atmosphere Flashcards
(18 cards)
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
How is pollution caused by combustion?
- when a fuel burns, the gases released to the atmosphere include carbon dioxide, water vapour, carbon monoxide, sulphur dioxide and oxides of nitrogen
- solid particles and unburned hydrocarbons may also be released that form particulates in the atmosphere
What are the issues regarding sulphur dioxide and oxides of nitrogen?
Sulphur dioxide and oxides of nitrogen cause respiratory problems in humans and cause acid rain. Acid rain damages plants and buildings
What problems do particulates cause?
- Particulates, such as carbon particles, cause global dimming by reducing the amount of sunlight that reaches the earth’s surface.
- Particulates cause health problems for humans because of damage to the lungs
