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AIR AND WATER - Coggle Diagram
AIR AND WATER
AIR
FRACTIONAL DISTILLATION OF AIR
The air is obtained through intake pipes and passed through very fine filters to remove any solids.
This air is then cooled to -80°C (using heat exchangers). At this temperature water vapor and carbon dioxide are solids and are removed as they can cause severe blockages.
The air minus water and carbon dioxide is cooled down further to below 200°C at which most of the air liquefies
The liquid air is pumped into a fractional column where it is gradually allowed to warm. They turn into gases, which rise and condense in different fractions according to their boiling points
The gases are collected separately before being stored in tanks and cylinders ready for use.
OXIDES OF NITROGEN
Catalytic Converters - The following reactions naturally occur to convert toxic pollutants into less toxic ones but at extremely slow rates: 2CO + O2 --> 2CO2 2NO + 2CO --> N2 + 2CO2 The catalyst in the converter in the exhaust system speeds up these reactions. Instead of the reactions taking place in the atmosphere at a slow rate the catalytic converter ensures these reactions take place before gases leave the exhaust
The main source of nitrogen oxide is from internal combustion engines. The oxides are created by the high temperatures generated by the engine that allow the normally unreactive nitrogen and oxygen to react in the atmosphere
RUSTING
conditions needed- oxygen and water
Sacrificial Protection - This method is based on the topic that more reactive metals corrode faster in comparison to iron. the metals used in sacrificial protection are zinc and magnesium.
RUST PREVENTION
Paint - steel bridges and railings are painted
Grease - Tools and machine parts are coated with grease or oil
Plastic Coating
Oiling
Galvanisation - adding a zinc coating to steel or iron to prevent rusting
COMMON POLLUTANTS
SULFUR DIOXIDE
burning of fossil fuels to generate electricity. reacts with water to form acid rain, causes wheezing and breathing problems for asthmatics
HEAVY METALS
released into the atmosphere by burning of fossil fuels and road transport emissions. lead is very toxic - weakness, brain damage and can be fatal too
NITROGEN OXIDES
primarily created by combustion in road transport. Causes severe damage to respiratory tracts
CARBON DIOXIDE
generated by the burning of fossil fuels in the production of electricity. threats to human existence and extinction of the earth
CARBON MONOXIDE
generated by incomplete combustion of fuels. symptoms of inhalation or exposure - headache, vomiting, can kill
The air is 78% nitrogen, 21% oxygen and the remaining 1% is argon, carbon dioxide, water vapour, helium, neon, krypton, xenon (which are mostly noble gases)
CARBON DIOXIDE AND METHANE
CARBON CYCLE
CO2 is emitted from respiration and combustion
CO2 is absorbed to make carbohydrates in photosynthesis
Animals eat these plants and the carbon consumed is released as CO2 formed during respiration
These animals and plants eventually die and decomposers feed on these dead organisms, the carbon is returned to the atmosphere as CO2
SOURCES OF METHANE
Production and use of fossil fuels
Livestock farming
Decomposition of vegetation
WHAT CARBON DIOXIDE IS A PRODUCT OF
The complete combustion of carbon-containing substances
respiration
reaction between acid and a carbonate
the thermal decomposition of a carbonate
GREENHOUSE GASES
EFFECTS
Electromagnetic radiation at most wavelengths from the sun passes through the Earth’s atmosphere
The Earth absorbs some radiation and thus warms up (essential for life on Earth). But some heat is radiated from the Earth as infrared radiation.
Some of this IR radiation is absorbed by greenhouse gases in the atmosphere
Atmosphere warms up leading to the greenhouse effect and global warming
EFFECTS OF GLOBAL WARMING
Extinction of species
Raising sea levels due to the melting of polar ice caps
Increased risk of skin cancer due to more dangerous UV rays hitting the surface of the Earth
Greenhouse gases maintain temperatures on Earth high enough to support life. They include: water vapour, CO & CH (methane)
WATER
TESTS
Cobalt(II) chloride:
○ Blue anhydrous cobalt(II) chloride turns pink in the presence of water
Copper(II) sulfate:
○ White anhydrous copper(II) sulfate turns blue in the presence of water
USES
Industry - cooling, as a solvent, drinking water for animals, irrigation, electricity generation
Home - drinking, cooking, plumbing, washing
TREATMENT OF WATER
Chlorination - chlorine is added to kill bacteria and other microbes
Filtration - water is passed through a filter of fine sand to remove any small particles
IMPLICATIONS OF INADEQUATE SUPPLY
needed for irrigation of crops
water is essential for life
Water covers about 2/3 of our plant, but the majority cannot be drunk directly
Humans need drinking water with low levels of dissolved salts and
microbes
NITROGEN AND FERTILISERS
HABERS PROCESS
Nitrogen and hydrogen are pressurized to 200 atmospheres and passed over a catalyst of iron(III) oxide at a temperature of approximately 450°C.
Within the reaction chamber the following reaction occurs: N2 +3H2→2NH3 Note that this reaction is both exothermic and reversible.
The reaction mixture is extracted and placed in a condensing chamber. The ammonia is separated as the condenser is allowed to cool. Since ammonia has the highest boiling point, it liquefies and is pumped out while the hydrogen and nitrogen remains gaseous and resumed into the reaction chamber
DISPLACEMENT OF AMMONIA
If an ammonium salt is reacted with a strong base, ammonia will be produced along with water and a salt
NH4Cl(aq)+NaOH(aq)->NH3(g)+H2O(l)+NaCl(aq)
NEED FOR NITROGEN, PHOSPHORUS AND POTASSIUM CONTAINING FERTILISERS
Compounds of nitrogen, phosphorus and potassium are used as fertilisers to improve agricultural productivity
plants need nitrogen, potassium and phosphorus in order to grow well, but can’t absorb it as a pure element- it must be a soluble salt (dissolved in water) that the roots can absorb
nitrogen → nitrate and ammonium salts
phosphorus → phosphate salts
potassium → potassium salts