Chemistry of the atmosphere Flashcards
How old is the earth
4.6 billion years
Describe the composition of the earth’s atmosphere
78% nitrogen
21% oxygen
0.9% argon
0.1% other gases
It was thought that when the earth was young it had an atmosphere more like those on Venus and Mars, high in carbon dioxide with some nitrogen. Explain how the atmosphere on earth may have changed.
Oxygen levels increased due to photosynthesis from algae and then more complex life forms as they developed
Carbon dioxide was reduced as it was used in photosynthesis and dissolved into the oceans
Describe what happens to carbon dioxide when it dissolves into the oceans
- It forms insoluble carbonate compounds such as calcium carbonate which sinks as sediment and eventually forms sedimentary rock.
- It forms soluble compounds which are taken in by animals to form their shells or skeletons. These then eventually become sediment and turn into rock as well.
- A lot of carbon dioxide was absorbed by algae and plants for photosynthesis. When they died their remains were buried in mud and compressed over millions of years forming crude oil and natural gas.
How is coal formed?
In swamps plants died and were buried and compressed over millions of years they formed coal, which is a type of sedimentary rock.
Describe a greenhouse gas
It is a gas which absorbs long wavelength infrared radiation given off by the Earth but does not absorb the sun’s radiation.
Explain the difference between the radiation given off by the Sun and the Earth
The radiation from the Sun contains electromagnetic radiation in the ultraviolet, visible and infra red regions. The earth being much cooler than the sun only gives off radiation in the infrared region, which has the longer wavelength.
Identify the most common greenhouse gases in the atmosphere
carbon dioxide
methane
water vapour
How have the amount of greenhouse gases changed on the last 100 years?
- The amount of water vapour is much the same
2. The amount of carbon dioxide and methane in the atmosphere has increased significantly.
What are the effects of increased amounts of carbon dioxide and methane in the atmosphere.
Greenhouse gases reflect the radiation from the Earth keeping the Earth warm.
Scientists believe that the increase in greenhouse gases are causing the Earth to warm up, this is known as climate change.
Identify some of the effects of climate change on the Earth
- Rising sea levels
- Changing amounts of rainfall
- Temperature and Water stress
- Wildlife changes
- Food production
6 Storms
Explain how climate change could affect wildlife
Some populations could be reduced if their habitat is destroyed eg polar bears in the polar regions as the ice caps melt
Some species may migrate further north as temperatures rise. Eg. some dragonflies have been found in the UK that are only usually found in warmer climates.
Plants may flower earlier, this can cause loss of crops such as apples if the temperature then drops and frosts kill the flowers.
Explain how climate change could affect food production
Changes in climate and rainfall would affect the crops grown in different regions due to drought, flooding, higher temperatures and differences in numbers of pests and pollinators.
Explain how climate change could affect sea levels
Rising temperatures would melt polar ice caps and glaciers causing the volume of the water in the oceans to increase.
In addition the higher temperature of the water itself increases volume still further.
Increases in volume would lead to a rise in sea levels which would cause catastrophic flooding in low lying countries like the Netherlands, Vietnam, Bangladesh and the Pacific islands.
Rising sea levels would also increase coastal erosion and tidal surges in port cities such as London and New York.
Explain how climate change could affect the number and intensity of storms
It is thought that climate change may increase the frequency and severity of storms. There is however mixed evidence, it appears that there is more rain falling in the severe storms but not that there are more hurricanes.
Explain how climate change could affect temperature and water stress
As temperatures rise it is likely that there will be a shortage of fresh water especially around the equator. This does not only affect humans but all creatures in the food chains.
What is meant by the term carbon footprint?
The amount of carbon dioxide and other greenhouse gasesgiven out over the full lifecycle of a product, service or event.
Describe how a carbon footprint is calculated.
It is the carbon dioxide released from the production, transportation use and disposal of an item Eg a plastic bag Energy to drill for the crude oil Energy in fractional distillation Energy in cracking alkanes Energy to polymerise the ethene Energy to transport the bag to the shop Energy to transport the bag to waste disposal More CO2 released if it is incinerated
Identify different methods for reducing your carbon footprint
Increase use of alternative energy Conserve energy Carbon capture and storage Carbon off setting Carbon taxes and licenses Carbon neutral fuels
Explain how Increasing the use of alternative energy can help reduce your carbon footprint
Using renewable energy sources such as solar, wind and nuclear reduces the need for burning fossil fuels thus reducing the carbon footprint as theirs is considerably lower than the fossil fuels.
Explain how energy conservation can help reduce your carbon footprint
Using less energy means that we burn fewer fossil fuels, we can do this by
- using more energy efficient engines in vehicles
- improving insulation in homes so that less heat escapes
- using more energy efficient boilers in heating systems
- using LED bulbs as they require less energy than halogen or filament bulbs
- using better detergents so that we can wash clothes at lower temperatures
- switching off electrical devices instad of leaving them on standby.
Explain how carbon capture and storage can help reduce your carbon footprint
A new technology which could reduce carbon emissions by up to 90%. The carbon dioxide produced by burning fossil fuels in a power station can be captured to prevent it being released into the atmosphere. It is then stored deep underground in rocks.
Explain how carbon offsetting can help reduce your carbon footprint
This is where something is put in place to compensate for the emmisions from elsewhere. Examples can include
- planting more trees
- setting up renewable energy projects such as wind farms
Explain how carbon taxes and licenses can help reduce your carbon footprint
By taxing fossil fuels governments can make fuel expensive, petrol and diesal are expensive in the UK because of tax. Car manufacturers compete to produce more fuel efficient cars to meet the demand for cars which are less expensive to run.
Governments can also issue licenses to limit the amount of greenhouse gases which can be released by businesses.
