Using resources Flashcards
(89 cards)
1
Q
What are ceramics?
A
non metallic solids with high melting points that aren’t made from carbon based compounds
2
Q
What can some ceramics be made from?
A
clay
3
Q
What is clay?
A
a soft material when it’s dug up out of the ground, so it can be moulded into different shapes
when it’s fired at high temperatures, it hardens to form a clay ceramic.
as clay can be moulded when wet and then be hardened, it’s ideal for making pottery and bricks
4
Q
What is another example of a ceramic?
A
glass
5
Q
What type of glass do we use?
A
soda-lime glass which is made by heating a mixture of sand, sodium carbonate and limestone until it melts. When the mixture cools, it comes out as glass
6
Q
What is borosilicate glass made from?
A
sand and boron trioxide which melts at higher temperatures than soda-lime glass
7
Q
What are composites?
A
- made of one material embedded in another
- fibres or fragments of a material (known as the reinforcement) surrounded by a matrix acting as a binder
- the properties of a composite depend on the properties of the material it is made from
8
Q
Name examples of composites
A
- wood
- fibreglass
- carbon fibre
- concrete
9
Q
How is fibreglass a composite?
A
- consists of fibres of glass embedded in a matrix made of polymer (plastic)
- low density
- very strong
- used for skis, boats
10
Q
How is carbon fibre a composite?
A
- polymer matrix
- reinforcement is made from long chain of carbon atoms or from carbon nanotubes
- very strong
- very light
- used in aerospace
11
Q
How is concrete a composite?
A
- made from aggregate(a mixture of sand and gravel)
- embedded in cement
- very strong
12
Q
How is wood a composite?
A
- natural composite of cellulose fibres
- held together by an organic polymer matrix
13
Q
What are polymers?
A
very large molecules formed when many small molecules called monomers, join together
14
Q
What do properties of polymers depend?
A
- what monomers they are made from
- how it’s made and the conditions under which they are made
15
Q
What are low density poly(ethene) made from?
A
- made from ethene
- at a moderate temperature
- under a high pressure and with a catalyst
- flexible and is used for bags and bottles
16
Q
What are high density poly(ethene) made from?
A
- ethene
- lower temperature
- pressure with a different catalyst
- more rigid
- used for water tanks and drainpipes
17
Q
What are the properties of thermosoftening polymers?
A
- made of individual tangled chains of polymers
- weak forces between the chains
- melt when heated so an be remoulded
- flexible
18
Q
What are the properties of thermosetting polymers?
A
- contains monomers that form cross links (covalent or ionic bonds)
- doesn’t melt when heated
- strong, hard
- rigid
19
Q
What are the properties of metals?
A
- malleable
- good conductors of heat and electricity
- ductile
- shiny
- stiff
20
Q
What is an alloy?
A
mixture of two or more metals
21
Q
What is the type of metal that we use everyday?
A
alloys
22
Q
What is bronze?
A
- an alloy of copper and tin
- harder than copper and it’s good for making statues, decorative objects and medals
23
Q
What is brass?
A
- an alloy of copper and zinc
- gold-like appearance
- more malleable than bronze
- water taps
24
Q
What type of gold is used as jewellery?
A
Gold used as jewellery is usually an alloy with silver, copper and zinc.
25
What is the proportion of gold in the alloy measured in?
carats
26
How many carats is 100% pure gold?
24 carat
27
What is steel?
alloys of iron that contain specific amounts of carbon and other metals
28
Why is pure iron not used?
- soft and easily shaped
- making it far too bendy for most uses
29
What are the properties of low carbon steel?
- softer
- easily shaped
- car bodies
30
What are the properties of high carbon steel?
- very strong
- inflexible
- brittle
- blades of cutting tools, bridges
31
What are stainless steels?
steels containing chromium and nickel
32
What are the properties of stainless steels?
- hard
- resistant to corrosion
- cutlery, containers for corrosive substances
33
What are properties of aluminium alloys?
- low density
- aircraft manufacture
- pure aluminium is too soft for making aeroplanes so it's alloyed with small amounts of other metals to make it stronger
34
What is corrosion?
destruction of materials by chemical reactions with substances in the environment
35
What is an example of corrosion?
rusting
36
What is needed for iron to rust?
Air and water
37
How can corrosion be prevented?
applying a coating that acts as a barrier, such as greasing, painting or electroplating
38
What is the sacrificial method?
involves placing a more reactive metal with the metal you want to protect
39
How is aluminium protected from corrosion?
oxide coating that protects the metal from further corrosion
40
What are finite resources?
- can't be formed quickly enough to be considered replaceable
- fossil fuels
- nuclear fuels
41
What are renewable resources?
- can be reformed at a similar rate to , or faster than we use them
- timber is renewable as trees can be planted following a harvest
42
What is sustainable development?
an approach to development that take account of the needs of present society while not damaging the lives of future generations
43
Copper ores are become scarce so what are the new ways of extracting copper from low-grade ores?
- phytomining
- bioleaching
44
How do the new methods of extracting copper differ from traditional methods?
avoid digging, moving and disposing of large amounts of rock
45
Describe how copper is extracted from low-grade ores by phytomining
- grow plants (on land containing copper ores)
- plants are burnt (to produce ash)
- ash dissolved in acid (to produce a solution of a copper compound)
- electrolysis of solution (containing a copper compound)
46
What is bioleaching?
- (the use of) bacteria
- to produce leachate solutions (that contain metal / copper compounds)
- extracted by electrolysis or displacement
47
Pros and cons of bioleaching and phytomining
+ cheap
+ smaller environmental impact
- slow
- land not available
- new technology
48
How can glass bottles be reused?
crushed and melted to make different glass products
49
How do we reduce the use of resources?
- reuse
- recycle
50
How can metals be recycled?
- by melting and recasting or reforming into different products
51
What are LCAs?
life cycle assessments assess the environmental impact of the entire lifetime of a product
52
What are the stages of the lifetime of a product?
- 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.
53
What are the problems with life cycle assessments?
- use of water, resources, energy sources and production of some wastes can be fairly easily quantified
- allocating numerical values to pollutant effects is less straightforward and requires value judgements, so LCA is not a purely objective process.
54
What have the life cycle assessments between plastic bags and paper bags shown?
even though plastic bags aren't biodegradable, they take less energy to make and have a longer lifespan than paper bags so they may be less harmful to the environment
55
Compare the raw materials of plastic bags and paper bags
Plastic bag: crude oil
Paper bag: timber
56
Compare the manufacturing and packaging of plastic bags and paper bags
Plastic bag: compounds needed to make the plastics are extracted from crude oil by fractional distillation, followed by cracking and polymerisation. Waste is reduced as the other fractions of crude oil have other uses
Paper bag: pulped timber is processed using lots of energy. Lots of waste is made
57
Compare the use of plastic bags and paper bags
Plastic bag: can be reused, can be used for other things as well as shopping, for example bin liners
Paper bag: usually only used once
58
Compare product disposal of plastic bags and paper bags
Plastic bag: recyclable but not biodegradable and will take up space in landfill and pollute land
Paper bag: biodegradable, non - toxic and can be recycled
59
What is potable water?
water that's been treated or is naturally safe for humans to drink - it's essential for life
not pure water in the chemical sense because it contains dissolved substances
60
What do methods used to produce potable water depend on?
- available supplies of water
- local conditions
61
What is fresh water?
water with low levels of dissolved substances that collects in the ground and in lakes and rivers
62
What is most potable water produced by?
- choosing an appropriate source of fresh water
- passing the water through filter beds
- sterilising
63
What is the treatment of fresh water?
- filtration where a wire mesh screens out large twigs and then gravel and sand beds filter out any solid bits
- sterilisation where the water is sterilised to kill any harmful bacteria or microbes and can be done by bubbling chlorine gas through it or by using ozone or ultraviolet light
64
What is done if supplies of fresh water are limited?
desalination of salty water or sea water which can be done by distillation or by processes that use membranes such as reverse osmosis, providing potable water
65
What happens during reverse osmosis?
- salty water is passed through a membrane that only allows water molecules to pass through
- ions and larger molecules are trapped by the membrane and so separated from the water
66
What may sewage and agricultural waste water require?
removal of organic matter and harmful microbes
67
What may industrial waste require?
removal of organic matter and harmful chemicals
68
What are the stages of waste water treatment?
- screening and grit removal
- sedimentation
- anaerobic digestion of solid sewage sludge
- aerobic digestion of effluent
69
What is screening?
removing any large bits of material like twigs of plastic bags as well as any grit
70
What is sedimentation?
the heavier suspended solids sink to the bottom to produce sludge while the less dense effluent floats on the top
71
What is aerobic digestion?
when air is pumped through the water to encourage aerobic bacteria to break down any organic matter - including other microbes in the water
the effluent in the settlement tank is removed by aerobic digestion
72
What is anaerobic digestion?
- anaerobic digestion of solid sewage sludge
- anaerobic digestion breaks down the organic matter in the sludge, releasing methane gas in the process
- the methane gas can be used as an energy source and the remaining digested waste can be used as a fertiliser
73
What is the Haber process for?
used to manufacture ammonia which can be used to produce nitrogen-based fertilisers
74
What are the raw materials for the Haber process?
nitrogen and hydrogen
75
Where is nitrogen obtained from?
the air which is about 80% nitrogen
76
Where is hydrogen obtained from?
- from reacting natural gas (methane) with steam
- it can also come from other source like crude oil
77
What are the steps of the Haber process?
- the purified gases are passed over a catalyst of iron at a high temperature (about 450°C)
- a high pressure (about 200 atmospheres)
- some of the hydrogen and nitrogen reacts and the mixture is cooled so that only ammonia liquefies
- the remaining hydrogen and nitrogen are recycled
78
Tell me about the temperature in the Haber process
- forward reaction is exothermic
- increasing the temperature will actually move the equilibrium the wrong way - away from ammonia and towards N2 and H2
- so the yield of ammonia would be greater at lower temperatures
- but lower temperatures mean a lower rate of reaction so the temperature is increased anyway to get a reasonable rate of reaction
79
Tell me about the pressure in the Haber process
- higher pressures favour the forward reaction
- moves the equilibrium towards ammonia and away from nitrogen and hydrogen
- so higher pressures increases the yield of ammonia
- the pressure is set as high as possible to give the best percentage yield, without making the plant too expensive to build
80
Tell me about the iron catalyst in the Haber process
- makes the reaction go faster which means that it reaches the equilibrium faster
- using a catalyst doesn't change the amount of products and reactants present at equilibrium
- without the catalyst, the temperature would have to be raised even further to get a quick enough reaction which would reduce the percentage yield even further and lead to higher energy costs
81
What are the 3 main elements plants need?
- nitrogen
- phosphorous
- potassium
82
What are NPK fertilisers?
formulations of various salts containing appropriate percentages of the elements
83
What can ammonia be used for in NPK fertilisers?
ammonia can be used to manufacture ammonium salts and nitric acid
84
What are obtained by mining in NPK fertilisers?
- potassium chloride
- potassium sulfate
- phosphate rock (treated with nitric acid or sulfuric acid to produce soluble slats that can be used as fertilisers)
85
How are NPK fertilisers produced in the industry?
- added directly to giant vats containing highly concentrated nitric acid
- results in a very exothermic reaction
- heat released is used to evaporate water from the mixture to make a very concentrated ammonium nitrate product
86
How are NPK fertilisers produced in the lab?
- reaction is carried out on a much smaller scale by titration and crystallisation
- ammonia solution is used and the reactants are at a much lower concentration than in industry so less heat is produce by the reaction and it's safer for a person to carry it out
- after the titration, the mixture needs to be crystallised to give pure ammonium nitrate crystals
- crystallisation isn't used in industry because it's very slow
87
If phosphate rock and nitric acid react, what is produced?
phosphoric acid and calcium nitrate
88
If phosphate rock and sulfuric acid react, what is produced?
calcium sulfate and calcium phosphate
89
If phosphate rock only reacts with phosphoric acid, what is produced?
calcium phosphate
