C10-Using resources Flashcards
What are finite resources?
Resources that are used up at a faster rate which they can be replaced.
What are renewable resources?
Resources that are used up at the same rate in which they can be replaced.
What are some examples of finite resources?
- Metal ores used to extract metals
- Crude oil used to make polymers
- Limestone to make petrol and concrete
- Crude oil to make the petrol, diesel and kerosene we use for transport
What are the methods of extracting metals from their ores and how do they work?
- Smelting (Then electrolysis)
- Displacement using scrap iron to extract copper
- Bioleaching (Having bacteria feed on the low-grade metal ore-this obtains a solution of copper ions-leachate)
- Phytomining (Plants are planted in soil containing a low percentage of copper ore, absorm it and are burnt in air-the ash contains high percentage of copper compound-then electrolysis)
What are the 4 stages in a life-cycle assessment?
- Raw material extraction
- Manufacture
- Use/Reuse/Maintainance
- Recycle/Waste management
What is potable water?
Water that is safe to drink
How is water made safe to drink?
- By firstly passing the untreated water through filter beds of sand and gravel to remove insoluble particles
- Sterilising the water (via chlorine or ozone to kill microorganisms or by passing UV light through the water)
What is a method to purify salty water?
Desalination via distillation or reverse osmosis
What is reverse osmosis?
Where water is put under high pressure and passed through a membrane that prevents most ions from passing through
How is waste water treated?
- Screening and grit removal to remove large particles
- Sedimentation to allow tiny particles to settle out from still water which produces sludge and effluent
- The sewage sludge is digested anaerobically by specific bacteria
- The effluent is treated with aerobic bacteria
What are the uses of ‘sludge’?
As a fertiliser of burnt to generate electricity
How can the effluent be made safer?
By filtering it one more time through a bed of sand and/or sterilised by UV light or chlorine
What is needed for the corrosion of iron?
Oxygen and water
What is the formula for rusting?
Iron + Oxygen + Water –>hydrated iron(III) oxide
What are ways to prevent rusting?
- Paint
- Oil or grease
- Plastic
- A less/more reactive (sacrificial metal)
What is a sacrificial method for protecting iron?
Adding zinc (galvanising)
What is a mixture of metal called?
Alloys
Why are alloys useful?
The differently-sized metal ions make it harder for the layers to slip-they are jammed in position
What are examples of Copper alloys?
- Bronze (copper and tin)
- Brass (copper and zinc)
What is gold mixed with?
Silver, copper and zinc-enables it to be stronger
What are examples of steel alloys?
- Low carbon steel
- High carbon steel
- Alloy steels-stainless steel contains chromium and nickel
What is the main glass we use?
Soda lime glass
How is soda lime glass made?
By melting a mixture of silicon dioxide (sand), sodium carbonate and limestone
What glass has the highest melting point?
Borosilicate glass made from heating sand with boron trioxide
How are clay ceramics made?
Wet clay is moulded then heated in a furnace to cause crystals to join together
What causes different polymers to be made?
Different monomers and different conditions in which the monomers were joined together
What are the 2 types of polyethene?
Low density and high density
What are the properties of low density polyethene compared to high density polyethene?
LDPE is softer so is generally used in more flexible products
What is the structure of LDPE compared to HDPE?
- LDPE has a structure where the polymer chains are branched and arranged randomly
- HDPE has less branching of polymer chains-the molecules line up much more closely
How is LDPE made vs HDPE?
At a lower pressure
What are the 2 main types of polymers?
Thermosoftening and thermosetting
How do thermosoftening polymers react when heated?
They don’t have covalent bonds between neighbouring polymer molecules so the molecules can move past each other when heated and the plastic melts
How do thermosetting polymers react when heated?
They have cross linking via covalent bonds so have much larger intramolecular forces-can’t be recycled but are used where it may get hot
What are composite materials?
Two or more materials with different properties
What components do composite materials have?
- The reinforcement
- The matrix-that binds the reinforcement together
Why can’t plants not use nitrogen in air?
It is insoluble in water
What nitrate ions can crops take in?
NO₃⁻
What is the formula in the Haber process?
N₂ + 3H₂ ⇌ 2NH₃
Nitrogen + Hydrogen ⇌ Ammonia
What are the raw materials for the haber process?
- Nitrogen from the air
- Hydrogen mainly from natural gases containing methane
What are the conditions in the Haber process?
- 450°C
- 200atm
- Iron catalyst
What happens in the Haber process?
- Nitrogen and hydrogen are pumped through pipes
- The gases are pressurised then heated
- The gases react over beds of iron catalysts and the reaction mixture is cooled so that the ammonia is liquified and removed
- The unreacted nitrogen and hydrogen are recycled
How is nitrogen extracted from air?
Fractional distillation
How is hydrogen produced from natural gases?
Steam is added to form hydrogen and carbon monoxide
What does increasing the pressure do in the Haber process and are there any compromises?
- Increases the rate of reaction
- Increases the amount of products made (more moles in reactants)
- Compromise: Need lots of energy and strong containers to withstand high ressures
What does increasing the temperature in the Haber process do and are there any compromises?
- Increases rate of reaction
- Decreases amount of products made (exothermic reaction)
- Compromise: Yield vs rate of reaction
What does adding a catalyst in the Haber process do?
It just speeds up the rate of reaction
What do fertilisers do?
Provide mineral ions needed for healthy growth in plants
How is nitric acid formed?
The oxidation of ammonia
What forms ammonium nitrate?
- Ammonia + Nitric acid –> Ammonium nitrate
- NH₃ + HNO₃ –> NH₄NO₃
What acids can ammonia also react with?
- Sulfuric acid-reacts at 60°C
- Phosphoric acid
What are the main fertilisers called?
NPK-Nitrogen, Phosphorus, Potassium
Why is nitrogen needed?
Healthy leaves
Why is phosphorus needed?
Healthy roots
Why is potassium needed?
To promote growth
How is sulfuric acid produced?
1) Sulfur + oxygen –> sulfur dioxide
2) Sulfur dioxide + oxygen ⇌ sulfur trioxide
3) Sulfure trioxide + water –>sulfuric acid
Where does potassium come from?
Mined potassium chloride and potassium sulfate
How is phosphate rock treated?
1) With nitric acid to produce phosphoric acid and calcium nitrate-phosphoric acid is the neutralised with ammonia to produce ammonium phosphate
2) With sulfuric acid to produce a single superphosphate-mixture of calcium phosphate and calcium sulfate
3) With phosphoric acid to produce triple superphosphate-calcium phosphate
