Using Earth's Resources Flashcards
1
Q
define sustainability
A
a resource or product being used to meet the needs of the current generation without compromising the ability to meet the needs of future generations to use that resource or product
2
Q
why can’t we drink natural water found in lakes and rivers etc?
A
contain harmful microorganisms and salts dissolved from rocks that the water as flowed over and through (these salts need to be at low levels to be safe for humans to drink)
3
Q
what is water quality that is safe to drink called?
A
potable water
4
Q
describe the process of production of potable water in temperate regions
A
- filter to remove solids
- precipitation reaction to remove harmful dissolved substances (flocculation)
- kill harmful microorganisms (adding Cl2 or O3 or using UV light)
- adjust water pH to neutral if necessary
5
Q
what are 2 processes of production of potable water in arid regions
A
- desalination of salt water
- reverse osmosis
6
Q
what does the desalination of salt water mean?
A
large scale distillation process (boil seawater) requiring a lot of energy, but is a fast process
7
Q
how does reverse osmosis produce potable water?
A
concentration (seawater) through the SPM to an area of very low salt concentration (fresh water). fresh water would then require further processing to enable it to become potable water. low energy but slower process.
8
Q
What sources can potable water be obtained from? (after treating)
A
fresh water, sea water, waste water
9
Q
what is waste water?
A
water which is produced by domestic and industry and contains harmful bacteria from household sewage and chemicals from industry
10
Q
what is sewage?
A
domestic and industrial waste; water contain effluent and sludge
11
Q
what is effluent?
A
liquid fraction of sewage
12
Q
what is sludge?
A
organic solid fraction of sewage
13
Q
industrial waste water must have further treatment compared to sewage and agricultural waste water; suggest why
A
it contains harmful chemicals
14
Q
what are the stages of waste water treatment??
A
- screening
- primary sedimentation tanks
- aeration
- final settling tanks
- sludge treatment
- burners
15
Q
what does screening do in waste water treatment?
A
removes large solids and grit by filtration
16
Q
what do primary sedimentation tanks do in waste water treatment?
A
organic waste (sludge) sinks to the bottom and remaining liquid (effluent) is removed from the top
17
Q
what does aeration do in waste water treatment?
A
good bacteria sink to bottom in sludge and treated water is returned to the environment
18
Q
what does sludge treatment do in waste water treatment?
A
anaerobic digestion of sludge by bacteria to produce methane and ammonia (used in fertilisers)
19
Q
what do burners do in waste water treatment?
A
methane burned for heat and electricity generation
20
Q
why are metals such useful materials?
A
good conductors and high MP
21
Q
what are metals used for?
A
- cells / batteries
- construction
- cars/ships/planes
- electrical circuits/wires
22
Q
what is a high grade ore?
A
a diminishing resource as they are so highly sought because of their relatively high metal content
23
Q
what is a low grade ore?
A
contain very small concentrations of metal and would require massive excavations to produce the same amount of metal and would be achieved from a high-grade ore (environmental damage and huge amounts of waste rock)
24
Q
describe the process of phytomining
A
- plants and other biomass are grown on top of land under which low-grade ores are situated
- over time the plants absorb metals in the form of minerals from the underlying ores and concentrate the metal within the plant material
- the plants are harvested, burnt, and the ash dissolved to make solutions
- electrolysis or displacement with scrap iron of the solution can then be used to produce the metal
- this method is a slow process as it relies upon the plants growing and concentrating the metal from the low-grade ore
25
describe the process of bioleaching
- a solution containing a certain type of bacteria is mixed with the low grade ore
- the bacteria react with the low-grade ore and produce a solution containing the metal from low-grade ore - this is a leachate
- the leachate can be used for electrolysis to produce the metal or the metal can be displaced from the leachate using scrap iron
26
what is corrosion?
the destruction of metals by chemical reaction with chemicals coming from the environment
27
why is prevention of corrosion key to sustainability of metal resources?
- corroded metals are much weaker than uncorroded metals and will lose many of their properties that make the metal useful in the first place
- this means corroded metals will need replacing which will affect the sustainability of that metal resource
28
what are 3 methods to prevent corrosion of metals?
barrier method, sacrificial protection, galvanisation
29
how does the barrier method work?
the coating acts as a barrier between the pure metal and the chemicals in the environment that would otherwise come into contact with the metal and corrode it
30
what are some examples of the barrier method?
- paint the metal
- cover the metal with oil or grease
- coat the metal with a film of plastic
31
why don't aluminium and magnesium corrode?
- they are reactive so the surface reacts with oxygen from the atmosphere
- this produces a metal oxide surface layer to protect the pure metal beneath
32
how does sacrificial protection work?
- the metal to protect has small pieces of a more reactive metal (sacrificial anodes) joined on its surface
- the more reactive metal will corrode instead of the metal which needs protection
- the sacrificial anodes need replacing as they get used up due to reacting with the corroding chemicals
33
what are some examples of sacrificial protection?
- zinc or magnesium are attached to the steel hulls of ships and oil rigs to stop the steel structures corroding in the seawater
- magnesium is attached to steel railway lines to stop them corroding
34
how does galvanising work?
- combines the barrier and sacrificial's methods of protection
- electrolysis is used to coat the less reactive metal with a more reactive one
- this means that even if the more reactive metal is scratched (barrier) the corrosive chemicals will react with the more reactive metal left instead of the less reactive
35
what is rusting?
the corrosion of steel or iron
36
what is the word equation for rusting
iron + water + oxygen ⇒ hydrated iron oxide
37
what are some features of glass that make it a useful material?
hard, transparent, unreactive, waterproof
38
what is soda lime glass made from?
silicon dioxide (sand), calcium carbonate, and sodium carbonate
39
what is borosilicate glass made from?
sodium dioxide (sand) and boron trioxide
40
what is soda lime glass used for?
windows and bottles - everyday glass
41
what is borosilicate glass used for?
laboratory and cooking glassware
42
why is borosilicate glass not soda lime glass used for lab and cooking glassware?
it is much more heat resistant
43
why is soda lime glass not borosilicate glass used for windows and bottles?
borosilicate is much more expensive
44
how are clay ceramics formed?
- wet clay is shaped and then fired in a kiln oven
- the high temp of the oven causes clay minerals to form a crystalline mesh of interlocking crystals
45
what are some features of clay ceramics?
hard, unreactive and heat resistant - because of their crystalline structure
46
what is a composite?
a material that is composed from 2 or more materials
47
what is a composite produced from?
all composites are produced from a matrix (binding) material with reinforced strands/rods/fibres running through the matrix
48
do composites have the same properties as the materials it is made from?
the properties of the composite will be very different to the individual properties of the matrix and reinforcing materials
49
what are some examples of composites?
- fibreglass
- MDF wood
- reinforced concrete
- carbon fibre
50
what is the matrix and reinforcing material for fibreglass?
matrix: polymer - reinforcing material: glass fibres
51
what is the matrix and reinforcing material for MDF wood?
matrix: adhesive - reinforcing material: wood chips
52
what is the matrix and reinforcing material for reinforced concrete?
matrix: concrete - reinforcing material: steel rods
53
what is the matrix and reinforcing material for carbon fibre?
matrix: polymer - reinforcing material: carbon nanotubes
54
what is fibreglass used for?
car bodies, yachts, canoes
55
what is MDF wood used for?
furniture
56
what is reinforced concrete used for?
bridges, skyscrapers, apartment blocks, hotels
57
what is carbon fibre used for?
tennis racquets, expensive car bodies
58
what are 4 types of polymer?
addition, condensation, thermosoft, thermoset
59
how are addition polymers made?
- many alkene monomers join to produce a polymer
- A C=C double bond breaks in each monomer allowing the many monomers to join together to produce a very long polymer chain
60
how are condensation polymers made?
2 different types of monomers join to create a polymer and water
61
how do thermosoft polymers work?
- there are very weak IMFs between the polymer chains
- low amounts of heat enable these forcces to break, allowing the polymer chains to move past each other
- the polymer becomes liquid and flows and takes a new shape
- on cooling, the IMFs reform and will hold the polymer chain in their new positions (new shape)
62
how do thermoset polymers work?
- there are very strong crosslinks between the polymer chains
- these crosslinks mean that they won't be overcome with large amounts of heat
- so the polymer chains won't be able to move past each other and so the polymer won't lose its shape
63
when are thermoset polymers useful?
where high heat will be an issue and the shape of the product needs to be maintained (eg saucepan handles, light sockets, plugs)
64
what do chemical reactions have, instead of a change in temperature?
they have a transfer of energy (chemical to thermal or vice versa)
65
give the chemical equation for the Haber process
N2 (g) + 3H2 (g) ‒Fe catalyst⇒ 2NH3 (g) exothermic
66
using Le Chatelier's principle, explain the optimum conditions for maximum ammonia yield from the haber process
- a low temperature would cause equilibrium to shift in the exothermic direction to release energy to the surroundings to oppose low temp, and the haber process is exothermic in the forward direction, therefore increasing yield of ammonia
- a high pressure would cause equilibrium to shift to the right to lower pressure (as there are the least gas molecules) to oppose high pressure
67
why is ammonia needed?
it is a key source material in the production of fertilisers - these are essential in food production as they improve soils and help crops grow successfully and quickly
68
why aren't optimum conditions used to produce ammonia? what is used instead?
- we actually use a medium temperature and moderate pressure, not low temp and high pressure
- this is because it improves the rate of reaction: the higher temps make it go faster, it is safer to use a lower pressure, and high pressures require a lot of energy to produce
69
why is nitrogen used in fertilisers?
they add extra nitrogen in the soils which helps plants make proteins which the plants use for growth
70
what is the formula for producing NPK fertilisers?
acid + base ⇒ soluble base + water
71
how do you produce ammonium nitrate?
- ammonia (NH3) can be oxidised to make nitric acid (HNO3)
- NH3 can be neutralised by HNO3 to make ammonium nitrate (NH4NO3)
- ammonia + nitric acid -> ammonium nitrate
72
what is the chemical equation for producing ammonium nitrate?
NH4OH + HNO3 --> NH4NO3 + H2O
73
what is the chemical formula of ammonium nitrate?
NH4NO3
74
what is ammonium nitrate a source for, in fertilisers?
nitrogen
75
how do you produce ammonium sulfate?
- ammonia + sulfuric acid -> ammonium sulfate
- ammonia from Haber process
- sulfuric acid from: a) sulfur + oxygen = sulfur dioxide b) sulfur dioxide + oxygen = sulfur trioxide c) sulfur trioxide + water = sulfuric acid
76
why can't phosphate be directly used as fertiliser?
it is insoluble, so has to be processed by reacting it with acids
77
is laboratory preparation of NPK fertilisers small or large scale?
small - batch process
78
describe the safety of laboratory preparation of NPK fertilisers
low concentration of reactants so low risk
79
describe equipment required for laboratory preparation of NPK fertilisers
burettes, pipettes, conical flasks, beakers
80
what are the reaction conditions required for laboratory preparation of NPK fertilisers?
RTP
81
what is the method of laboratory preparation of NPK fertilisers?
titration
82
is industrial preparation of NPK fertilisers small or large scale?
continuous large scale
83
describe the safety of industrial preparation of NPK fertilisers
high concentration of substances, high temperature and pressure, so high risk
84
describe equipment required for industrial preparation of NPK fertilisers
large reaction towers
85
what are the reaction conditions required for industrial preparation of NPK fertilisers?
high pressure and 60 degrees
86
what is the method of industrial preparation of NPK fertilisers?
large amounts of NPK products made from raw materials
87
what are 2 compounds of potassium used to make NPK fertilisers?
potassium chloride and potassium sulfate
88
how is potassium sulfate/chloride obtained from natural deposits in the earth?
mining
89
why is the reaction of phosphate rock to produce NPK fertilisers carried out at much higher concentrations in industry than the lab?
it is too dangerous to use high concentrations in the lab
90
why is the reaction of phosphate rock to produce NPK fertilisers separated out by crystallisation in the lab, but this technique isn't used in industry?
crystallisation is slower than other processes, so not used in industry, but fairly safe so used in labs
91
what is the chemical equation for producing ammonium sulfate?
2NH3 (aq) + H2SO4 (aq) -> (NH4)2SO4 (aq)
92
what is the chemical formula of ammonium sulfate?
(NH4)2SO4
93
what is ammonium sulfate a source for, in fertilisers?
nitrogen
94
how do you produce ammonium phosphate?
ammonia + phosphoric acid = ammonia phosphate + water
95
what is the chemical formula for ammonia phosphate?
(NH4)3PO4
96
what is ammonia phosphate a source for, in fertilisers
phosphorous and nitrogen
97
how do you make potassium nitrate?
ammonium nitrate + potassium hydroxide = potassium nitrate + water
98
what is the chemical formula for potassium nitrate?
KNO3
99
what is potassium nitrate a source for, in fertilisers?
potassium and nitrogen
100
what is the formula for potassium chloride?
KCl
101
what is the formula for potassium sulfate?
K2SO4
102
phosphate rock + nitric acid = ?
phosphoric acid + calcium nitrate
103
phosphate rock + sulfuric acid = ?
single superphosphate (calcium sulfate + calcium phosphate)
104
phosphate rock + phosphoric acid = ?
triple superphosphate (calcium phosphate)
