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Environment and resources - Coggle Diagram
Environment and resources
Composition of atmosphere
Primarily nitrogen - 78.09% (about 78%)
Then Oxygen - 20.95% (about 21%)
Then argon - 0.93% (about 1%)
And finally 0.03% traces of other gases
Evolution of atmosphere
Gases released in volcanic eruptions form early atmosphere (H2O, CO2, CH4, N2, NH3)
Lightning and UV radiation split up molecules of CH4 and NH3 to make more C02 and nitrogen
Early bacteria could live without O2 and started making the first O2 in the atmosphere through photosynthesis
First plants evolved making more oxygen through photosynthesis (6CO2 + 6H2O = 6C6H12O6 + 6O2) But it took a long time for % oxygen to increase
Eventually the crust absorbed all oxygen it could so O2 concentration rose to the level where animals could evolve. A layer of ozone developed to block out harmful UV radiation
Population increase means more resources consumed means more CO2 in atmosphere
Burning more fossil fuels increases amount of CO2
Deforestation means less photosynthesis so less CO2 is removed from the atmosphere
When oceans formed, carbon dioxide dissolved in the water and carbonates were precipitated, producing sediments which reduced amount of CO2 in the atmosphere
Algae and plants photosynthesising reduced percentage of carbon dioxide in the atmosphere
Formation of sedimentary rocks and fossil fuels decreased carbon dioxide
Water
Pollution
Sewage
Microorganisms
Excess Nutrients
e.g fertilisers running off into water supplies
Waste water
Chemical waste
Radioactive waste
Thermal waste
Water purification (to remove pollution)
three stage process:
Filtration
Sedimentation
Chlorination
Extracting copper
How to extract copper from malachite ore:
Heat CuCO3 so it breaks down into CuO (thermal decomposition)
React CuO with sulfuric acid to form CuSO4
CuSO4 can be purified in one of two ways:
Displacement
Iron + copper sulfate = Copper + Iron sulfate
Electrolysis
Phytomining
'Phyto' is to do with plants
Process:
Grow crops on soil containing metal concentration too low for conventional extraction (complexing agents can be added to increase metal uptake of crop)
Burn plant material once harvested
Small volume of plant ash (bio-ore) containing high concentration of target metal
Smelt bio ore to yield metal
As plants grow they absorb dissolved ions in the soil through their roots - once harvested we can extract the metals from these ions through the ashes of the plants
Advantages
Reduces need to obtain ore by mining
Therefore reduces damage to environment as mining for metal ores involves quarries that destroy natural habitats and noise, dust and traffic
Disadvantages
Slow process
Bioleaching
Certain bacteria can feed on low grade ores to produce an acidic solution that contains copper ions e.g. sulfide ions to produce sulfuric acid with copper ions within
This solution is called a leachant
Bioleaching doesn't need high temperatures BUT
produces toxic substances that can damage the enivronment