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

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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)

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3
Q

what is water quality that is safe to drink called?

A

potable water

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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
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5
Q

what are 2 processes of production of potable water in arid regions

A
  • desalination of salt water
  • reverse osmosis
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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

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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.

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8
Q

What sources can potable water be obtained from? (after treating)

A

fresh water, sea water, waste water

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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

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10
Q

what is sewage?

A

domestic and industrial waste; water contain effluent and sludge

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11
Q

what is effluent?

A

liquid fraction of sewage

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12
Q

what is sludge?

A

organic solid fraction of sewage

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13
Q

industrial waste water must have further treatment compared to sewage and agricultural waste water; suggest why

A

it contains harmful chemicals

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14
Q

what are the stages of waste water treatment??

A
  • screening
  • primary sedimentation tanks
  • aeration
  • final settling tanks
  • sludge treatment
  • burners
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15
Q

what does screening do in waste water treatment?

A

removes large solids and grit by filtration

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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

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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

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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)

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19
Q

what do burners do in waste water treatment?

A

methane burned for heat and electricity generation

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20
Q

why are metals such useful materials?

A

good conductors and high MP

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21
Q

what are metals used for?

A
  • cells / batteries
  • construction
  • cars/ships/planes
  • electrical circuits/wires
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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

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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)

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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
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25
Q

describe the process of bioleaching

A
  • 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
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26
Q

what is corrosion?

A

the destruction of metals by chemical reaction with chemicals coming from the environment

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27
Q

why is prevention of corrosion key to sustainability of metal resources?

A
  • 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
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28
Q

what are 3 methods to prevent corrosion of metals?

A

barrier method, sacrificial protection, galvanisation

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29
Q

how does the barrier method work?

A

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

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30
Q

what are some examples of the barrier method?

A
  • paint the metal
  • cover the metal with oil or grease
  • coat the metal with a film of plastic
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31
Q

why don’t aluminium and magnesium corrode?

A
  • 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
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32
Q

how does sacrificial protection work?

A
  • 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
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33
Q

what are some examples of sacrificial protection?

A
  • 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
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34
Q

how does galvanising work?

A
  • 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
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35
Q

what is rusting?

A

the corrosion of steel or iron

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36
Q

what is the word equation for rusting

A

iron + water + oxygen ⇒ hydrated iron oxide

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37
Q

what are some features of glass that make it a useful material?

A

hard, transparent, unreactive, waterproof

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38
Q

what is soda lime glass made from?

A

silicon dioxide (sand), calcium carbonate, and sodium carbonate

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39
Q

what is borosilicate glass made from?

A

sodium dioxide (sand) and boron trioxide

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40
Q

what is soda lime glass used for?

A

windows and bottles - everyday glass

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41
Q

what is borosilicate glass used for?

A

laboratory and cooking glassware

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42
Q

why is borosilicate glass not soda lime glass used for lab and cooking glassware?

A

it is much more heat resistant

43
Q

why is soda lime glass not borosilicate glass used for windows and bottles?

A

borosilicate is much more expensive

44
Q

how are clay ceramics formed?

A
  • 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
Q

what are some features of clay ceramics?

A

hard, unreactive and heat resistant - because of their crystalline structure

46
Q

what is a composite?

A

a material that is composed from 2 or more materials

47
Q

what is a composite produced from?

A

all composites are produced from a matrix (binding) material with reinforced strands/rods/fibres running through the matrix

48
Q

do composites have the same properties as the materials it is made from?

A

the properties of the composite will be very different to the individual properties of the matrix and reinforcing materials

49
Q

what are some examples of composites?

A
  • fibreglass
  • MDF wood
  • reinforced concrete
  • carbon fibre
50
Q

what is the matrix and reinforcing material for fibreglass?

A

matrix: polymer - reinforcing material: glass fibres

51
Q

what is the matrix and reinforcing material for MDF wood?

A

matrix: adhesive - reinforcing material: wood chips

52
Q

what is the matrix and reinforcing material for reinforced concrete?

A

matrix: concrete - reinforcing material: steel rods

53
Q

what is the matrix and reinforcing material for carbon fibre?

A

matrix: polymer - reinforcing material: carbon nanotubes

54
Q

what is fibreglass used for?

A

car bodies, yachts, canoes

55
Q

what is MDF wood used for?

A

furniture

56
Q

what is reinforced concrete used for?

A

bridges, skyscrapers, apartment blocks, hotels

57
Q

what is carbon fibre used for?

A

tennis racquets, expensive car bodies

58
Q

what are 4 types of polymer?

A

addition, condensation, thermosoft, thermoset

59
Q

how are addition polymers made?

A
  • 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
Q

how are condensation polymers made?

A

2 different types of monomers join to create a polymer and water

61
Q

how do thermosoft polymers work?

A
  • 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
Q

how do thermoset polymers work?

A
  • 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
Q

when are thermoset polymers useful?

A

where high heat will be an issue and the shape of the product needs to be maintained (eg saucepan handles, light sockets, plugs)

64
Q

what do chemical reactions have, instead of a change in temperature?

A

they have a transfer of energy (chemical to thermal or vice versa)

65
Q

give the chemical equation for the Haber process

A

N2 (g) + 3H2 (g) ‒Fe catalyst⇒ 2NH3 (g) exothermic

66
Q

using Le Chatelier’s principle, explain the optimum conditions for maximum ammonia yield from the haber process

A
  • 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
Q

why is ammonia needed?

A

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
Q

why aren’t optimum conditions used to produce ammonia? what is used instead?

A
  • 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
Q

why is nitrogen used in fertilisers?

A

they add extra nitrogen in the soils which helps plants make proteins which the plants use for growth

70
Q

what is the formula for producing NPK fertilisers?

A

acid + base ⇒ soluble base + water

71
Q

how do you produce ammonium nitrate?

A
  • 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
Q

what is the chemical equation for producing ammonium nitrate?

A

NH4OH + HNO3 –> NH4NO3 + H2O

73
Q

what is the chemical formula of ammonium nitrate?

A

NH4NO3

74
Q

what is ammonium nitrate a source for, in fertilisers?

A

nitrogen

75
Q

how do you produce ammonium sulfate?

A
  • 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
Q

why can’t phosphate be directly used as fertiliser?

A

it is insoluble, so has to be processed by reacting it with acids

77
Q

is laboratory preparation of NPK fertilisers small or large scale?

A

small - batch process

78
Q

describe the safety of laboratory preparation of NPK fertilisers

A

low concentration of reactants so low risk

79
Q

describe equipment required for laboratory preparation of NPK fertilisers

A

burettes, pipettes, conical flasks, beakers

80
Q

what are the reaction conditions required for laboratory preparation of NPK fertilisers?

A

RTP

81
Q

what is the method of laboratory preparation of NPK fertilisers?

A

titration

82
Q

is industrial preparation of NPK fertilisers small or large scale?

A

continuous large scale

83
Q

describe the safety of industrial preparation of NPK fertilisers

A

high concentration of substances, high temperature and pressure, so high risk

84
Q

describe equipment required for industrial preparation of NPK fertilisers

A

large reaction towers

85
Q

what are the reaction conditions required for industrial preparation of NPK fertilisers?

A

high pressure and 60 degrees

86
Q

what is the method of industrial preparation of NPK fertilisers?

A

large amounts of NPK products made from raw materials

87
Q

what are 2 compounds of potassium used to make NPK fertilisers?

A

potassium chloride and potassium sulfate

88
Q

how is potassium sulfate/chloride obtained from natural deposits in the earth?

A

mining

89
Q

why is the reaction of phosphate rock to produce NPK fertilisers carried out at much higher concentrations in industry than the lab?

A

it is too dangerous to use high concentrations in the lab

90
Q

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?

A

crystallisation is slower than other processes, so not used in industry, but fairly safe so used in labs

91
Q

what is the chemical equation for producing ammonium sulfate?

A

2NH3 (aq) + H2SO4 (aq) -> (NH4)2SO4 (aq)

92
Q

what is the chemical formula of ammonium sulfate?

A

(NH4)2SO4

93
Q

what is ammonium sulfate a source for, in fertilisers?

A

nitrogen

94
Q

how do you produce ammonium phosphate?

A

ammonia + phosphoric acid = ammonia phosphate + water

95
Q

what is the chemical formula for ammonia phosphate?

A

(NH4)3PO4

96
Q

what is ammonia phosphate a source for, in fertilisers

A

phosphorous and nitrogen

97
Q

how do you make potassium nitrate?

A

ammonium nitrate + potassium hydroxide = potassium nitrate + water

98
Q

what is the chemical formula for potassium nitrate?

A

KNO3

99
Q

what is potassium nitrate a source for, in fertilisers?

A

potassium and nitrogen

100
Q

what is the formula for potassium chloride?

A

KCl

101
Q

what is the formula for potassium sulfate?

A

K2SO4

102
Q

phosphate rock + nitric acid = ?

A

phosphoric acid + calcium nitrate

103
Q

phosphate rock + sulfuric acid = ?

A

single superphosphate (calcium sulfate + calcium phosphate)

104
Q

phosphate rock + phosphoric acid = ?

A

triple superphosphate (calcium phosphate)