Chemistry of the atmosphere Flashcards
(19 cards)
What percentage of the atmosphere is nitrogen?
80%
What percentage of the air is oxygen?
20%
What are the other gases in the atmopshere?
- carbon dioxide
- water vapour
- noble gases
Why is the evidence of the early atmosphere limited?
because of the time scale of 4.6 billion years
What is one theory of the earth’s atmosphere?
One theory suggests that during the first billion years of the Earth’s existence there was intense volcanic activity that released gases that formed the early atmosphere and water vapour that condensed to form the oceans
What is the most popular theory of the Earth’s atmosphere?
At the start of this period the Earth’s atmosphere may have been like the atmospheres of Mars and Venus today, consisting of mainly carbon dioxide with little or no oxygen gas.
Volcanoes also produced nitrogen which gradually built up in the atmosphere and there may have been small proportions of methane and ammonia.
When the oceans formed carbon dioxide dissolved in the water and carbonates were precipitated producing sediments, reducing the amount of carbon dioxide in the atmosphere.
What is the word equation for photosynthesis?
carbon dioxide + water -> glucose + oxygen
Approximately when did algae first produce oxygen?
2.7 billion years ago
How did carbon dioxide in the atmosphere decrease?
- Algae and plants decreased the percentage of carbon dioxide in the atmosphere by photosynthesis.
- Carbon dioxide was also decreased by the formation of sedimentary rocks and fossil fuels that contain carbon.
How were crude oil and natural gas formed?
from deposits of plankton and form reservoirs under the seabed
What are example of greenhouse gases?
- water vapour
- carbon dioxide
- methane
What is the greenhouse effect?
- the sun emits short wavelength radiation which passes through the Earth’s atmosphere as it isn’t absorbed by greenhouse gases
- the short wavelength radiation reaches the Earth’s surface, is absorbed, and then re emitted as long wavelength radiation
- this radiation is absorbed by greenhouse gases in the atmosphere
- the greenhouse gases then re radiate in all directions - including back towards the Earth
- the longwave radiation is thermal radiation, so it result sin the warming of the surface of the earth
What are 4 potential effects of global climate change?
- an increase in global temperature could lead to polar ice caps and glaciers melting, causing a rise in sea levels, increased flooding in coastal areas and coastal erosion
- changes in rainfall patterns
- the frequency and severity of storms may also increase
- changes in temperature and the amount of water available in a habitat may affect wild species, leading to differences in their distribution
What does carbon footprint mean?
the total amount of carbon dioxide and other greenhouse gases emitted over the full life cycle of a product, service or event
How can carbon footprint be reduced?
by reducing emissions of carbon dioxide and methane
What could the products of combustion be?
- carbon dioxide
- water vapour
- carbon monoxide
- sulfur dioxide
What are the problems of carbon particulates?
- if inhaled they can get stuck in the lungs and cause damage
- bad for the environment as they reflect sunlight back into space and help to produce more clouds
- means that less light reaches the Earth - causing global dimming
What are the problems of carbon monoxide?
- really dangerous because it can stop your blood from doing its proper job of carrying oxygen around the body
- binds to haemoglobin in your blood that normally carries oxygen
- no colour or smell so can be hard to detect
What are the problems of acid rain?
- when sulfur dioxide or oxide of nitrogen mix with the water in the clouds, they react with water to form sulfuric acid or nitric acid
- then falls as acid rain
