9. Chemisry Of The Atmosphere Flashcards
(20 cards)
What are three two theories as to why the earths atmosphere has changed over time?
- volcanoes give out gases
- oceans, algae and green plants absorbed carbon dioxide
- green plants and algae produced oxygen
How does the theory of volcanoes giving out gases work (3 steps)?
- The first billion years of earths history were pretty explosive- the surface was covered in volcanoes that erupted and released lots of gases
- The early atmosphere was probably mostly made up of carbon dioxide with virtually no oxygen (like Mars and Venus)
- Volcanic activity also released nitrogen which built up in the atmosphere over time as well as water vapour and small amounts of methane and ammonia
How does the theory of oceans, algae and green plants absorbing carbon dioxide work? (5 steps)
- When water vapour is condensed it forms the oceans
- Lots of carbon dioxide dissolved into oceans so was removed from the early atmosphere
- The dissolved carbon dioxide went through reactions to form carbonate precipitates that formed sediments on the seabed
- Later marine animals evolved whose shells and skeletons contained some of these carbonates from the oceans
- Green plants and algae evolved and absorbed some of the carbon dioxide so that they could carry out photosynthesis
How does carbon get trapped in fossil fuels and rocks? (6 points)
- When plants, plankton and marine animals die they fall to the seabed and are buried by layers of sediment
- Over millions of years, they become compressed and form sedimentary rocks, oil and gas- trapping the carbon within them
- Things like coal, crude oil and natural gas that are made by this process are called fossil fuels
- Crude oil and natural gas are formed from deposits of plankton. These fossil fuels form reservoirs under the seabed when they get trapped in rocks
- Coal is a sedimentary rock made from thick plant deposits
- Limestone is also a sedimentary rock made mostly of calcium carbonate deposits from the shells and skeletons of marine organisms.
How does the theory of green plants and algae producing oxygen work? (5 points)
- Green plants and algae absorbed oxygen by photosynthesis and let out oxygen
- Algae evolved first- about 2.7 billion years ago
- Over the next billion years or so, green plants also evolved
- As oxygen levels built up in the atmosphere over time, more complex animals could evolve
- About 200 million years ago the atmosphere reached a similar composition as today
What is the composition of today’s atmosphere?
- 80% nitrogen
- 20% oxygen
- small amounts of other gases such as carbon dioxide, noble gases and water vapour
How does the greenhouse effect work? (4 points)
- Greenhouse gases like carbon dioxide, methane and water vapour act as an insulating layer in the earths atmosphere
- All particles absorb certain frequencies of radiation. Greenhouse gases don’t absorb the incoming short wavelength radiation but do absorb the long wavelength radiation
- They they re-radiate the radiation in all directions including back towards earth
- The long wave radiation is thermal radiation so results in the warming of the surface of the earth
What are 4 ways that human activity increases the amount of greenhouse gases in the atmosphere?
- deforestation- less photosynthesis
- burning fossil fuels- releases carbon dioxide
- agriculture- farm animals produce methane
- creating waste- more landfill sites means more carbon dioxide and methane is released by decomposition
What are some of the effects of climate change?
- increases in global temperatures= polar ice caps melting= rise in sea levels= increased flooding= coastal erosion
- changes in rainfall patterns along with changes in temperatures affects ability to produce foods
- frequency and severity of storms may increase
- changes in temperature and the amount of water available in certain habitats may affect wild species, leading to differences in their distribution
What is a carbon footprint?
A measure of the amount of carbon dioxide and other greenhouse gases released over a full life cycle of something
Why is measuring a carbon footprint hard?
There are so many factors to consider
What are 5 ways to reduce carbon footprints?
- Use renewable or nuclear energy
- Use more efficient processes to conserve energy and cut waste
- Governments could tax companies or individuals for emission of greenhouse gases
- Governments could put a cap on emissions of all greenhouse gases companies make and sell licences on emissions up to that cap
- Use technology to capture carbon dioxide
Why is it hard to reduce carbon footprints?
- lots of work to be done on new technologies
- technologies are expensive
- changes could affect economic growth of countries
- hard to make international agreements without everyone on board
- not enough education
How can an individual reduce their personal carbon footprint?
- choose to cycle or walk over using a car
- reduce how much they use air travel
- do anything that saves energy in the home
What is produced as a result of incomplete combustion (not enough oxygen)?
- particulates
- carbon monoxide
- carbon dioxide
What problems can particulates cause?
- if particulates are inhaled, they can get stuck in the lungs and cause damage and respiratory problems
- they’re bad for the environment too, they reflect sunlight back into space causing global dimming
What problems can carbon monoxide cause?
- stops blood from carrying oxygen around the body- binds to haemoglobin
- lack of oxygen can leading to fainting, comas or death
- hard to detect which makes it more dangerous
How is sulfur dioxide released?
During the combustion of fossil fuels such as coal that contain sulfur impurities- the sulfur become oxidised
How are nitrogen oxides created?
From a reaction between the nitrogen and oxygen in the air caused by the heat of burning (e.g. in internal combustion engines of cars)
What are the problems of sulfur dioxide and nitrogen oxides?
- when they mix with water in clouds they make acid rain due to them being diluted
- acid rain kills plants, damages buildings and statues and makes metal corrode
- they are bad for human health and can cause respiratory problems if breathed in
