Chemistry of the Atmosphere Flashcards
% of gases in atmosphere today:
approx. 80% nitrogen
approx. 20% oxygen
less than 1% other gases, e.g. carbon dioxide, water vapour, noble gases
What was the first phase of the evolution of the atmosphere?
Volcanic activity
What did intense volcanic activity release?
Carbon dioxide, steam, ammonia and methane
What was the early atmosphere when volcanic activity took place like?
Mostly carbon dioxide and no oxygen gas
What was the second phase of the evolution of the atmosphere?
Oceans, algae and green plants absorb carbon dioxide
How where oceans formed?
Water vapour condensed and rained
How do oceans remove carbon dioxide from the atmosphere?
Carbon dioxide dissolves in the oceans
What did dissolved carbon dioxide in oceans do?
Went through a series of reactions and formed carbon precipitates that formed sediments on the seabed
How do algae and green plants reduce the amount of carbon dioxide in the atmosphere?
Through photosynthesis
What do marine animals’ shells and skeletons contain?
Carbonates from the oceans
What happened to the carbon that organisms took from the atmosphere and oceans?
They became locked up in rocks and fossil fuels after the organisms died
How are fossil fuels formed?
Plants, plankton and marine animals die, fall onto seabed, get buried by layers of sediment, become compressed and form sedimentary rocks, oil and gas, trapping carbon within them
How is crude oil and natural gas formed?
From deposits of plankton - form reservoirs under seabed when trapped inside rocks
What is coal made from?
Thick plant deposits
What is limestone?
A sedimentary rock
What is limestone made of?
Calcium carbonate deposits from the shells and skeletons of marine organisms
What was the third phase of the evolution of the atmosphere?
Green plants and algae produce oxygen
What evolved first to produce oxygen?
Algae
What did the percentage increase of oxygen allow?
More complex life, like animals to evolve
What is released into the atmosphere during combustion of fossil fuels?
Carbon dioxide and water vapour
When does incomplete combustion take place?
When there isn’t enough oxygen present
What does incomplete combustion release?
Carbon monoxide and particulates
What are particulates?
Solid particles of soot or unburnt fuel
What can happen if particulates are inhaled?
They can cause respiratory problems - they are small enough to access the airways to the lungs are some are small enough to penetrate the alveoli
Why are particulates bad for the environment?
Because they or the clouds they produce reflect sunlight back into space, meaning less light reaches Earth - causes global dimming
How can carbon monoxide be reduced?
By a catalytic converter
Why is carbon monoxide dangerous in the body?
It can stop your blood from carrying oxygen by binding to the haemoglobin so less oxygen can be transported around the body - lack of oxygen - lead to fainting, coma, death
Why is carbon monoxide hard to detect?
It has no colour or smell
When is sulfur dioxide released?
During combustion of fossil fuels that contain sulfur impurities
How is nitrogen oxide created?
From nitrogen and oxygen in the air reacting because of the heat of burning
What happens when sulfur dioxide or nitrogen oxide mix with clouds?
They form dilute sulfuric acid or dilute nitric acid
What does dilute sulfuric acid or dilute nitric acid (formed when mixed with clouds) do?
It falls as acid rain - kills plants, damages buildings and statues, makes metal corrode
How is sulfur dioxide and nitrogen oxide bad for human health?
If breathed in they can cause respiratory problems
How can the production of sulfur dioxide be reduced?
Removal of sulfur from the fuel prior to combustion
Using scrubbers in power stations to remove SO2
How can the production of nitrogen oxide be reduced?
Using a catalytic converter to convert the nitrogen oxide into nitrogen gas
