Chemistry Of Atmosphere Flashcards
What is the composiiton of gases in the atmosphere (present)
80% nitrogen
20% oxygen
Small percenatge of carbon dioixde, water vapour and noble gases
What was the Earth’s early atmosphere like and how has it changed (main changes and causes)
Time scale only 4.6 billion years ago
1) One theory suggetss that the first billion years of the Earth’s existence was intense volcanic activity that releases gases to form the atmosphere and water vapour condensed to form oceans. Mainly carbon with no oxygen.
2) Volcanoes also produced nitrogen which built up gardually along with small proportions of methane and ammonia
3) Oceans formed carbon dioixde dissolved in water and carbonates were precipitated producing sediments, reducing carbon dioixde in the atmosphere
How has oxygen increased in the atmosphere
Algae and plants produce oxygen through photosynthesis
This happened 2.7 billion years ago and plants have evolved and the percentage of oxygen have enabled animals to also evolve
How has carbon dioxide decreased
Algae plants decreased the percentage of carbon dioixde in the atmosphere by photosynthesis
Carbon dioxide decreased through sedimentary rocks and fossil fuels containing carbon
How has deposits of limestone,coal, crude oil and natural gas been formed
Limestone: made of calcium carbonate deposits from shells and skeletons of marine life
Coal: made from thick plant deposits
Crude oil and natural gas: Formed from plankton. These fossil fuels form reservoirs under the seabed when they die off and get trapped , heated and pressurised.
Describe the greenhouse effect in terms of the interaction of short and long wavlength radiation with matter
Greenhouse gases maintain temp on Earth to support life. Water vapour , carbon dioixde and methane are greenhouse gases.
Greenhouse gases don’t absorb the incoming short wavelength radiation from the sun but absorb the reflected long wavelength radiation. Once absorbed thermal energy is re-radiated in all directions.
Human activities that increase amount of greenhouse gases
Deforestation: fewer trees means less Co2 is removed from the atmosphere though photsynthesis
Fossil fuels: These are burnt which release greenhouse gases such as CO2
Agriculture: more farm animals produce more methane through their digestive processes
Creating waste: more landfill sites and more waste from agriculture means more CO2 and methane released by decomposiiton of wasts
Describe the effects of global climate change on the Earth and the implications of this
1) Increase in temp leads to polar ice caps or ice sheets to melt causing rising sea levelsnand thretaens low lying and coastal inhabitants
2) Changes in rainfall pattern mau cause regions to get too much or little water. This may effect the agricultusl aspect of an area (malnutrition)
3) Frequency and severity of storm increase (leads to many death, injuries and destruction)
4) changes in temp and the amount of water available in a habitat may affedt wild species, leading to differences in distribution
What is carbon footprimt
Total amount of carbon dioixde and other greenhouse gases emitted over the full life cycle of a product, service or event.
Actions to reduce emissions of carbon dioixde and methane and why can actions for this be limited
Ways to reduce emissions:
renewable energy sources are nuclear , use more efficient processes , government to tax companies or individuals on production of greenhouse gases , put a cap on emissions for companies , carbon catching and storing.
Why are action limited:
Work to be done on alternstive technologies that resukt in a lower CO2 emission , effect on economic growth and people , difficulty to educate of changes needed to be made.
Describe how carbon monoxide, soot, sulfur dioixde and oxides of nitrogen are produced by burning fuel
Incomplete combustion- not enough oxygen for all the fuel to burn which releases harmful gases or particles.
Sulfur dioxide: released during combustion of coal that contains sulfur impurities which become oxidised. The gases mix with clouds and form dilute sulfuric acid .
Oxides of nitrogen: Created from a reaction between the nitrogen and oxygen in the air, caused by the heat of burning (internal combustion engines)
Descibe and explain the problems causes by an increased amount of pollutants in the air
Carbon monoxide: stops the body from carrying oxygen by binding onto haemoglobin which could lead to fainting, coma or death (it is undetectable)
Particulates: when inhaled could get stuck in the lungs and cause damage (respiratory problems) and cause global dimming
Sulfur dioxide: Falls as acid rain which corrodes metal and kills plants and causes respiratory problems
Oxides of nitrogen: Falls as acid rain which corrodes metals and kills organisms and may also caused respiratory problems
