C9 - Chemistry of the Atmosphere Flashcards
What is phase 1 of the Earth’s early atmosphere?
Volcanoes gave out gases - Mostly carbon dioxide.
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
What planets do we think the Earth’s atmosphere from phase 1 was most like?
Mars and Venus (or Titan, a moon)
How did nitrogen levels increase in Earth’s early atmosphere to now?
As volcanic activity also released nitrogen, which built up in the atmosphere over time. As well as water vapour and small amounts of ammonia and methane
What was phase 2 of Earth’s early atmosphere?
Oceans (from condensed water vapour), algae and green plants absorbed carbon dioxide
What was phase 3 of Earth’s early atmosphere?
The green plants and algae produced oxygen
How did levels of carbon dioxide reduce?
1) Green plants and algae took in CO2 for photosynthesis
2) Oceans absorbed CO2 as well, being trapped in sedimentary rocks
What happens when plants, plankton and marine animals die?
They fall into the seabed and get buried by layers of sediment. Over millions of years, they become compressed and form sedimentary rocks, oil and gas - trapping the carbon within them
What is limestone?
A sedimentary rock - mostly made of calcium carbonate deposits from the shells and skeletons of marine organisms
Why is it difficult to tell what the Earth’s early atmosphere was like?
Because the average temperature was around 400C, and with no oxygen there was no life that we can date
How were crude oil and natural gases formed?
From deposits of plankton. These fossil fuels form reservoirs under the seabed when they get trapped in rocks
How is coal made?
It is a sedimentary rock made from thick plant deposits
What do the shells and skeletos of marine animals contain?
Carbonates from the oceans that absorbed CO2
Which plant evolved first?
a) Trees
b) Grass
c) Algae
d) Daisies
c) Algea - around 2.7 billion years ago
Complete the sentence:
As oxygen levels built up over time in the atmosphere.
More complex life (like animals) could evolve
Give some rough percentages of Earth’s atmosphere today
Nitrogen - 78-80%
Oxygen - 20%
CO2 - 0.03% around
Water vapour - <1%
What are greenhouse gases?
Gases that act as an insulating layer in the Earth’s atmosphere - which allows it to be warm enough to support life
How do these forms of human activity affect the amount of greenhouse gases in the atmosphere?
a) Deforestation
b) Burning fossil fuels
c) Agriculture
d) Creating waste
a) Fewer trees = less CO2 removed from atmosphere by photosynthesis
b) Carbon trapped in these fuels is released
c) More farm animals produce more methane through their digestive processes
d) More landfill sites and more waste from agriculture means more CO2 and methane released by decomposition of waste
All particles absorb certain frequencies of radiation. Greenhouse gasses don’t absorb the incoming short wavelength from the sun - but they do absorb long wavelength that gets reflected back towards the Earth. This wavelength is thermal radiation, so it results in warming the surface of the Earth. What s this?
The greenhouse effect
Increasing carbon dioxide is linked to what?
Climate change
What are the dangerous consequences of climate change?
1) An increase in global temperature could lead to polar ice caps melting - rising the sea levels, increasing flooding in coastal areas and coastal erosion
2) Changes in rainfall patterns (amount, timing and distribution) may cause some regions to get too much/ little water. This along with changes in temperature, may affect the ability of certain regions to produce food
3) The frequency and severity of storms may also increase - extreme weather
4) Changes in temperature and the amount of water available in a habitat may affect wild species, leading to differences in their distribution
What is a carbon footprint?
A measure of the environmental impact a product has over its full life cycle
A measure of the amount of CO2 and other greenhouse gases released over the full cycle of something. That can be a service (school bus), an event (Olympics), a product (toastie maker) - almost anything
How can you reduce carbon footprints?
1) Renewable energy sources or nuclear energy used instead of fossil fuels
2) More efficient processes may conserve energy and cut waste. Lots of waste decomposes to release methane, so this will reduce methane emissions
3) Gov could tax companies or individuals based on amount of greenhouse gases they emit
4) Gov could put a cap on emissions of all greenhouse gases that companies make, then sell licenses for emissions up to that cap
5) Also tech that captures CO2 produced by burning fossil fuels before it’s released into the atmosphere, then it can be stored deep underground in cracks in the rock such as old oil wells
Why is reducing carbon footprints difficult?
Gov worries about economic growth of communities - could be bad for people’s well being
Not everyone is on board, so some people won’t sacrifice their economic developments
Still a lot of work to be done on alternative technologies that result in lower CO2 emissions
It is difficult to change your lifestyle, and there isn’t enough education on how to do so
Combustion of fossil fuels releases what?
Gases and particles - they contain hydrocarbons. So, during combustion the carbon and hydrogen articles are oxidises forming carbon dioxide and water vapour to be released
What does the incomplete combustion of fossil fuels cause? How is this dangerous?
(Incomplete means not enough oxygen). Solid particles of soot (carbon) called particulates and unburnt fuel are released, and carbon monoxide can be produced too
Dangerous because if particulates are inhaled, they can get stuck in the lungs and cause damage, leading to respiratory problems
Also they’re bad for the environment. They (or the clouds they help produce) reflect sunlight back into space, meaning less light reaches Earth, causing global dimming
Carbon monoxide is odourless and colourless and poisonous (as binds to haemoglobin in red blood cells which is irreversible)
How is carbon monoxide dangerous?
It can stop blood from carrying oxygen around the body, as it binds to haemoglobin in the red blood cells, which is irreversible, so oxygen can’t travel to the muscles. It is odorlus, colourless and tasteless, so it can easily kill due to oxygen debt
Sulfur dioxide is released when?
During the combustion of fossil fuels, such as coal, that contain sulfur impurities - the sulfur in the fuel becomes oxidised
How are oxides of nitrogen made?
In engines - created from a reaction between nitrogen and oxygen in the air, caused by the heat of the burning
How are oxides of nirogen and sulfur dioxide harmful to the environment?
When they mix with clouds, they fall as acid rain, which kills plants and damages buildings and statues. It also makes metal corrode
Also bad for human health, as they cause respiratory problems when breathed in
