CHEMISTRY OF THE ATMOSPHERE Flashcards
How do scientists think the early atmosphere was formed?
Surface used to be covered in lots of volcanoes which erupted and released lots of gases
What gases was the early atmosphere probably made up of?
Lots of carbon dioxide
Almost no oxygen
What gases do volcanoes release?
Nitrogen
Water vapour
Small amounts of methane and ammonia
How were oceans formed?
When water vapour in the atmosphere condensed
How was carbon dioxide removed from the early atmosphere (oceans)?
It was dissolved in the oceans and went through reactions to form carbon precipitates that formed sediments on the seabed
How was carbon dioxide removed from the early atmosphere (plants)?
Green plants and algae evolved and absorbed some of the carbon dioxide for photosynthesis
How does carbon become locked up in rocks and fossil fuels after organisms die?
Plankton and marine animals die and fall to seabed
Buried by layers of sediment
Become compressed and form sedimentary rocks, oil and gas (and trap carbon)
How is crude oil and natural gas formed?
Formed from deposits of plankton (under seabed when trapped in rocks)
How is coal formed?
Sedimentary rock made from thick plant deposits
How is limestone formed?
Sedimentary rock made from calcium carbonate deposits from shells and skeletons of marine organisms
What increased oxygen levels in the atmosphere?
Production of oxygen by photosynthesis from green plants and algae
What are some greenhouse gases?
Carbon dioxide
Methane
Water vapour
What do greenhouse gases do?
Act as an insulating layer in the Earth’s atmosphere
What do greenhouse gases do in our atmosphere?
They don’t absorb incoming short wavelength radiation from the sun
Instead they absorb the long wavelength radiation that gets reflected back from earth
They re-radiate this longwave thermal radiation in all directions (like back to Earth)
What are some forms of human activity that affect the amount of greenhouse gases in the atmosphere?
Deforestation
Burning fossil fuels
Agriculture
Creating waste e.g. landfill sites. decomposition
What could be the consequences of an increase in global temperatures?
Polar ice caps melting causing rise in sea level, flooding and coast erosion
Frequency and severity of storms may increase
Changes in temp and water availability may affect species and distribution
Change in rainfall pattern and temp so may affect the ability to grow certain foods
What are carbon footprints?
A measure of the amount of carbon dioxide and other greenhouse gases released over the full life cycle of something (service, event, product)
What are ways to reduce a carbon footprint?
Use renewable or nuclear energy sources instead of fossil fuels
Use more efficient processes that conserve energy and cut waste
Governments could tax companies based on the amount of greenhouse gases they use
Technology that captures co2
What are the limitations of reducing carbon footprint?
Could affect economic growth
Technology needs to be more advanced
Hard to make international agreements as most countries do not want to sacrifice their economic development
Not enough education/people do not want to change everyday lifestyle
What happens during combustion of hydrocarbons?
Carbon and hydrogen in hydrocarbons are oxidised so that carbon dioxide and water vapour are released into the atmosphere
What do fossil fuels contain (crude oil, coal etc.)
Hydrocarbons
When does complete combustion occur?
When there is plenty of oxygen
When does incomplete combustion occur?
When there is not enough oxygen
What happens during incomplete combustion?
Solid particles (particulates) of soot (carbon) and unburnt fuel are released and carbon monoxide is produced (and sometimes co2)
What problems can particulates in the air cause?
Can get stuck in lungs and cause respiratory problems
Bad for environment as they can reflect sunlight back into space so less light reaches Earth (global dimming)
What is carbon monoxide?
Colourless, odourless, dangerous gas
What does carbon monoxide do to the human body?
Binds to haemoglobin in blood so less oxygen is able to be transported around the body causing fainting, a coma or even death
When is sulfur dioxide produced?
During combustion of fossil fuels that contain sulfur impurities
What happens to the sulfur in sulfur dioxide during combustion?
It becomes oxidised
How is nitrogen oxide produced?
When a reaction between nitrogen and oxygen in the air caused by heat of burning
What happens when sulfur dioxide mixes with clouds?
Produces dilute surfic acid which falls as acid rain
What happens when nitrogen oxide mixes with clouds?
Produces dilute nitric acid which falls as acid rain
What can acid rain do?
Kills plants
Damages buildings and statues
Corrodes metal
How are sulfur dioxide and nitrogen oxide bad for humans?
Cause respiratory problems when breathed in
