Using Resources Flashcards
What is sustainable development?
Development that meets the needs of current generations 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?
Sterilising agents used for potable water include chlorine, ozone or ultraviolet light.
- Chlorine is a toxic gas so the amount added to water has to be carefully monitored
- Using ultraviolet light to kill microbes avoids adding chemicals to the water but is more expensive
How is desalination carried out?
Desalination can be done by distillation or by processes that use membranes such as reverse osmosis. These processes require large amounts of energy
What is reverse osmosis?
Sea water is passed through a membrane that only allows through the water molecules. It needs high pressure to push the water through the membrane. The high pressure requires a lot of energy to produce
How is wastewater produced and how is it treated?
-Urban lifestyles and industrial processes produce large amounts of waste water that require treatment before being released into the environment
-Sewage and agricultural waste water require removal of organic matter and harmful microbes
-Industrial waste water may require removal of organic matter and harmful chemicals
What are the processes involved in sewage treatment?
Sewage treatment includes:
- 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 disadvantages of traditional mining?
Avoids the disadvantages of traditional mining methods of digging, moving and disposing of large amounts of rock
What is phytomining?
Phytomining uses plants to absorb metal compounds from the soil. The plants are harvested and then burned to produce ash that contains the metal compounds
What is bioleaching?
Bioleaching uses bacteria to produce leachate solutions that contain metal compounds
What is the main advantage and disadvantage of bioleaching and phytomining?
These methods need less energy than traditional methods, and can work on low concetration ores but are slow to carry out
Describe the stages of LCAs
Life cycle assessments are carried out to assess the environmental impact of products in each of these stages:
- extracting and processing raw materials
- manufactoring 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?
The reduction in use, reuse and recycling of materials by end users reduces the use of limited resources, energy consumption, waste and environmental impacts
What are the advantages and disadvantages of recycling?
Advantages: less acid rain metal ore reserves last longer / conserved energy for extraction saved less mining/quarrying less waste less landfill creates local employment
Disadvantages: collection problems transport problems/ cost of transport difficult to separate metal from appliances/sort
What is corrosion and how is it prevented?
Corrosion is the destruction of materials by chemical reactions with substances in the environment e.g rusting
Corrosion can be prevented by applying a coating that acts as a barrier, suc as greasing, painting or electroplating. These methods stop the air of water coming into contact with the metal
Describe the sacrificial protection
Some coatings are reactive and may contain corrosion inhibitors or a more reactive metal
If two metals are in contact the more reactive metal will corrode instead of the less reactive one
Steels
Alloys of iron that contain specific amounts of carbon and other metals. High carbon steel is strong but brittle. Low carbon steel is softer and more easily shaped. Steels containing chromium and nickel are hard and resistant to corrosion
Bronze
An alloy of copper and tin, used for making statues and decorative objects
Brass
An alloy of copper and zinc used for producing water taps and door fittings
Gold
Used as jewellery is usually an alloy with silver, copper and zinc
How are the properties of polymers determined?
The properties of polymers depend on what monomers they are made from and the conditions under which they are made. For example, low density and high density polyethene are produced from ethene, using different catalysts and reaction conditions
Describe the structures of thermosoftening and thermosetting polymers
Thermosetting polymers do not melt on heating. The polymer molecules are linked to each other by strong cross-links. Thermosoftening polymers soften easily on heating and can then be remoulded, keeping the new shape on cooling. The polymer molecules are attracted to each other by weak intermolecular forces
How is glass made?
Most of the glass is soda-lime glass, made by heating a mixture of sand, sodium carbonate and limestone. Borosilicate glass, made from sand and boron trioxide, melts at higher temperatures than soda-lime glass
How are clay ceramics made?
Clay ceramics, including pottery and bricks, are made by shaping wet clay and then 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/fragments together
Outline the key points of Haber process
- the purified H2 and N2 gases are passed over Fe catalyst at a high temperature (about 450 degrees c) and a high pressure (about 200atm)
- Fe speeds up the rate of reaction, so that a lower temp could be used in the process
- some of the hydrogen and nitrogen reacts to form ammonia N2 + 3H2 –><– 2NH3
- the reaction is reversible so ammonia breaks down again into nitrogen and hydrogen
- on cooling, the ammonia liquefies and is removed. The remaining hydrogen and nitrogen are recycled. This means almost no material is wasted
- Ammonia is used for production of nitrogen-containing fertilisers
The Haber process uses high T and P conditions. Explain why this is so and why this is a compromise
The conditions are a comrpomise between rate and the yield:
- the reaction is exothermic. An optimum temperature of 450 degrees is used. Using a lower temp would give a higher yield, but the rate of NH3, production would be too slow
- a pressure of 200 atm is used. Using a higher pressure would give 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?
Compounds of nitrogen, phosphorus and potassium are used as fertilisers to improve agricultural productivity. NPK fertilisers compounds of all three elements
How is industrial production of NPK fertilisers achieved?
Ammonia can be used to manufacture ammonium salts. The ammonium sulfate, phosphate, and nitrate can be produced by reaction of ammonia with the requisite acid
How is the phosphate rock utilised in the production of fertilisers?
-Phosphate rock is reacted with nitric acid to produce phosphoric acid and calcium nitrate
- Phosphate rock can be reacted 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
