Using Resources Flashcards
What is sustainable development
Development that meets the needs of the current generation without compromising the ability of future generations to meet their own needs
In the UK, potable water is produced by
- Choosing an appropriate source of fresh water
- Passing the water through filter beds to remove any solids
- Sterilising to kill microbes
What are the sterilising agents for potable water
- Chlorine (carefully monitor amount)
- Ultraviolet or ozone light kills microbes (more expensive)
How is desalination carried out
Reverse osmosis, requires large amount of energy
What is reverse osmosis
Sea water is pushed through a membrane
Only allows through water molecules
Needs high pressure to push water through
The high pressure requires a lot of energy
How is wastewater produced and how is it treated
- Urban lifestyles and industrial processes produce large amounts of waste water that require treatment
- Sewage and agricultural waste water require removal of organic matter
- Industrial waste water may require removal of harmful chemicals
What are the processes involved in sewage treatment
- Screening and grit removal
- Sedimentation to produce sewage sludge and effluent
- Anaerobic digestion of sewage sludge
- Aerobic biological treatment of effluent
What do new methods of mining avoid in terms of traditional mining?
Avoids disadvantages of traditional mining methods of digging, moving and disposing of large amounts of rock
What is Phytomining?
- Plants absorb metal compounds from the soil
- Concentrates in plant tissues
- Plants are harvested
- Burned to produce ash that contains metal compound
- Then use electrolysis to extract pure metal
What is bioleaching?
Bacteria
Produces leachate solutions
That contain metal compounds
Advantages and disadvantages of bioleaching and phytomining?
Methods need less energy than traditional methods and can work on low concentration ores but are slow to carry out
Describe the stages of LCA’s
Assess environmental impacts of:
- Extracting and processing raw materials
- Manufacturing and packaging
- Use and operation during its lifetime
- Disposal at the end of its useful life including transport and distribution at each stage
How do we reduce the use of resources.
- Reuse and recycling of materials by end users
Advantages of recycling
- Less acid rain
- Metal ore reserves last longer
- Quarrying less waste landfill creates local employment
What is corrosion and how is it prevented?
Destruction of materials by chemical reactions with substances in the environment, e.g. rusting
Can be prevented by applying a coating that acts as a barrier, such as greasing, painting or electroplating
Describe the sacrificial protection
Some coatings are more reactive and that metal, and will corrode instead of the less reactive one
What is Bronze and what’s its use
- Alloy of copper and tin
- Used for making statues and decorative objects
What is Brass and what’s its use
- Alloy of copper and zinc
- Used for producing instruments, water taps and door fittings
How are the properties of polymers determined?
- Depend on what monomers they are made from and the conditions under which they are made
Describe the structures of thermosoftening and thermosetting polymers
Thermosetting do not melt on heating, polymers are linked by strong cross-links
Thermosoftening soften easily on hearing and then can be remoulded, keeping new shape on cooling, polymer molecules are attracted to each other by weak IM forces
How is glass made
- Most of the glass we use soda-lime glass, made by heating a mixture of sand, limestone and sodium carbonate
How are clay ceramics made
Shaping wet clay and heating in a furnace
How are composites formed
Fibres or fragments of one material are surrounded by a binder/matrix material that holds these fibres/fibres together
Key points of the Haber process
- Purified H2 and N2 gasses are passed over Fe catalyst at 450°C and 200atm
- Fe speeds up rate of reaction, so a lower temp can be used
- Some of the hydrogen and nitrogen form to make ammonia
- The reaction is reversible so ammonia breaks down again into nitrogen and hydrogen
- On cooling, ammonia liquefies and is removed, remaining hydrogen and nitrogen are recycled
- Ammonia is used for production of fertilisers
Why is Haber process at such a high temp and pressure?
Conditions are a compromise between rate and the yield:
- Reaction is exothermic, lower temp would give higher yield but would be too slow
- Higher pressure gives a higher yield, but would be too expensive because of the cost of energy to produce the high pressure
How are compounds of nitrogen, phosphorus and potassium used?
To make NPK fertilisers to improve agricultural productivity
How is the phosphate rock utilised in the production of fertilisers
-React with nitric acid to produce phosphoric acid and calcium nitrate
- react with sulfuric acid to produce a mixture of calcium phosphate and calcium sulfate
- Phosphate rock can be reacted with phosphoric acid to produce calcium phosphate
