chemistry of the atmosphere Flashcards
(28 cards)
What is the current composition of the earth’s atmosphere?
-78% nitrogen
-21% oxygen
-0.9% argom
-Small amounts of other gases
(including carbon dioxide, water
vapour and noble gases)
How long ago was the earth formed?
4.6 billion years ago
What was the composition of the earth’s early atmosphere?
-95% Carbon dioxide
-4% Water vapour
-Traces of nitrogen, ammonia, and methane
Where did gases come from in the early atmosphere?
Volcanic activity?
What did the early atmosphere resemble?
That of mars or venus today
What happened to levels of oxygen and carbon dioxide?
-Oxygen increased
-Carbon dioxide decreased
How did oxygen increase?
-Photosynthesis
How did carbon dioxide decrease?
-When the oceans formed, carbon dioxide dissolved into the water and formed soluble carbonates. These were then precipitated as sedimentary rocks (e.g. limestone).
-Carbon dioxide dissolved in the oceans was also absorbed by algae for photosynthesis.
-Carbon dioxide was absorbed by plants, which then died. Some of these became fossil fuels (coal, oil, and gas) which contain carbon.
-Compression and heating over millions of years formed trees into coal, and plants/small organisms into oil/natural gas
Give some examples of greenhouse gases?
-Water vapour
-Carbon dioxide
-Methane
How does the greenhouse effect work?
-Electromagnetic radiation passes through the Earth’s
atmosphere
-The Earth absorbs most of the radiation and heats up
-The Earth emits infrared radiation
-Some of the infrared radiation is transmitted into space
-Greenhouse gases absorb the infrared and release energy in
all directions
-This warms up the Earth’s lower atmosphere
What is carbon footprint?
The total amount of greenhouse gases it produces during its lifetime
What must you consider in order to calculate the carbon footprint of an OBJECT?
-mining and transporting the parts
-generating electricity to power it
-using the object
-the object is disposed of/recycled
What must you consider in order to calculate the carbon footprint of a PERSON?
-mining and transporting the parts
-generating electricity to power it
-using the object
-the object is disposed of/recycled
How is the natural greenhouse effect increased?
-Carbon dioxide is produced through respiration of animals and volcanic activity.
-Methane is produced through the formation of coal and decomposition (usually in wetlands).
How is the greenhouse effect enhanced?
-Carbon dioxide is released through deforestation and the burning of fossil fuels (coal, oil, and gas).
-Methane is released through the decomposition of landfills, burning biomass and digestive emissions from cattle.
-Nitrous oxides are released through car exhaust fumes and fertilisers used on farms
What is climate change?
The long-term alteration of the Earth’s climate
What is the main evidence for humans causing climate change?
The strong correlation between the rise of CO2 levels due to
human activities and the rise in global temperature
What should you consider when evaluating the quality of evidence on something like climate change?
- Who did the research.
- Who funded the research.
- What methods were used to collect and analyse the data.
- Which organisation is reporting/publishing the evidence.
What is the source and effect of Carbon Dioxide?
-Complete combustion
-The greenhouse effect
What is the source and effect of Carbon Monoxide?
-Incomplete combustion
-Poisonous, odourless, and colourless gas
What is the source and effect of soot?
-Incomplete combustion
-Irritates lining of the lungs, can cause cancer, global dimming
What is the source and effect of unburned hydrocarbons?
-Hydrocarbon fuel molecules which have not been oxidised
-Reacts with other pollutants to create ozone (in smog), global dimming
What is the source and effect of sulphur dioxide?
-Combustion of fuel that contains sulphur
-Causes acid rain, which harms the environment
What is the source and effect of nitrous oxide?
-Inside vehicle engines
-Causes acid rain and smog (harmful to health)
