resources Flashcards
(75 cards)
1
Q
how do humans use the earths resources
A
- modern farms to produce cotton, fuel (biofuel)
- replaced with a synthetic alternative, eg synthetic rubber from crude oil, rather than tree sap
2
Q
finite vs renewable and examples
A
- cannot be reformed as quickly as they are being used, eg fossil fuels
- can be reformed as quickly as they are being used, eg wood
3
Q
what is potable water
A
water that is safe to drink, as it has:
- low levels of dissolved salts
- low levels of microbes
4
Q
pure water vs potable water
A
pure water contains no dissolved substances, only h2o, whereas potable water contains dissolved substances
pure water has pH 7, potable water may differ
5
Q
how is potable water produced
A
- rainwater has low levels of dissolved substances
- rainwater collects as surface water (lakes, rivers, reservoirs) or groundwater (aquifers), creating fresh water sources
- fresh water source chosen
- water passes through filter beds to remove large solids eg leaves
- water sterilised using chlorine, ozone, or uv light to kill microbes
6
Q
why and how is producing potable water different in some countries different to the uk
A
- fresh water, which has low levels of dissolved minerals, is scarce
- seawater, which has high levels of dissolved minerals, may be only water available
- desalination required to reduce levels of dissolved minerals to provide potable water
7
Q
desalination methods and their issues
A
- distillation
- reverse osmosis (pass water through membranes)
require lots of energy, expensive
8
Q
how to purify water
A
distillation
- put conical flask containing water sample on tripod and gauze
- connect top of flask to collecting tube that leads into a test tube that is sat in an ice bath
- gently heat water using bunsen burner
- vapour travels along collecting tube and condenses in cold test tube to for distilled water
9
Q
how to test if water is pure
A
test for pH
test for dissolved solids
10
Q
how to test if water is pure using pH and why is this not enough
A
place some of water onto universal indicator paper. paper would turn green for pH 7
water could still contain dissolved solids
11
Q
how to test if water is pure using dissolved solids
A
- find mass of empty evaporating basin using balance
- fill basin with water and place on tripod and gauze
- gently heat using bunsen burner until it has evaporated
- weigh basin again once cooled
- mass will increase if water contained dissolved solids as crystals will form
12
Q
what makes water waste water
A
- lots of organic molecules eg and faeces urine and faeces
- lots of harmful microorganisms eg bacteria
13
Q
where does waste water come from
A
- drains into sewers after human use
- nutrient run-off from agricultural fields
14
Q
how is waste water treated
A
- screening: sewage passes through a mesh to remove grit
- sedimentation: left to settle in sedimentation tanks to separate into semi-solid sludge and liquid effluent
- sludge removed to be broken down via anaerobic digestion, producing biogas which can used for electricity by burning or for farming as fertilisers
- air bubbled through liquid effluent to encourage aerobic bacteria to multiply and digest the organic molecules and harmful microorganisms
- effluent safely discharged to rivers or sea
15
Q
how is waste water treated for industry use
A
harmful chemicals must first be removed then it can be treated as normal
16
Q
how easy is potable water to produce by ground water vs by salt water vs by waste water
A
- ground water: easiest, safe once treated with chlorine. could be polluted by fertilisers
- salt water: requires desalination, requires lots of energy, expensive
- waste water: requires many purification steps, only done if water is scarce
17
Q
why does extracting copped need to be made more sustainable
A
copper ore is becoming scarce, meaning it has to be extracted from low-grade ores.
low-grade ores contain very little copper, meaning it may be harder to extract copper cost effectively
18
Q
how are metals extracted from low-grade ores
A
phytomining
bioleaching
19
Q
how does phytomining extract metal compounds from low-grade ores
A
- plants grown in soil that contains the wanted metal compound
- plants absorb the metal compound, however cannot use it, meaning it builds up in tissue
- plants harvested and burned, ash has high conc of metal
20
Q
how does bioleaching extract metal compounds from low-grade ores
A
- bacteria mixed with the low-grade ore
- bacteria carry out chemical reactions to produce a leachate
- the leachate contains wanted metal compound
21
Q
what must be done after phytomining/bioleaching
A
metal needs to be extracted from the metal compound produced
- displacement (eg scrap iron, for copper)
- electrolysis
22
Q
pros of phytomining and bioleaching
A
- economically extract metals from low-grade ores, metal ore may be limited
- less damaging, as there is no digging/transporting
23
Q
what are life cycle assessments
A
assesses environmental impact of a product
24
Q
first stage considered in life cycle assessment
A
extracting and processing the raw material
- to produce plastics, crude oil must be extracted, transported, separated, and cracked. lots of energy needed - more fossil fuels burned
- extracting metals from ores produces toxic waste products
25
seconds stage considered in life cycle assessment
manufacturing and packaging
- requires energy, meaning more fossil fuels burned
- may release harmful waste products
26
third stage considered in life cycle assessment
usage of product
- more batteries = more toxic waste produced
27
fourth stage considered in life cycle assessment
disposal of product
- energy required to dispose harmful chemicals
- energy required to transport products to disposal centres
28
compare stage 1 of life cycle assessment for plastic bag vs paper bad
- plastic: crude oil (non renewable), extraction can be harmful to habitats eg oil spill
- paper: trees (renewable), felling trees can be harmful to habitats eg forests
29
compare stage 2 of life cycle assessment for plastic bag vs paper bad
both chemically processed, requires energy, releases waste products
30
compare stage 3 of life cycle assessment for plastic bag vs paper bad
plastic: strong, often reused eg as bin liners
paper: easily broken, often used only once
31
compare stage 4 of life cycle assessment for plastic bag vs paper bad
plastic: must be tranported. non-biodegradable, pollute land and fill up landfills
paper: heavier, more energy to transport. biodegradable, dont fill landifills
32
issue of life cycle assessments
- cannot be certain how damaging a stage is, meaning numerical values are estimated & inaccurate
- can be biased
33
what is corrosion
the destruction of materials by chemical reactions with substances in the environment
34
how to investigate the condition required for rusting
in three test tubes, place an iron nail in:
- distilled water and open to air
- in boiled distilled water (no dissolved air) and covered in oil (no air can dissolve)
- on anhydrous calcium chloride powder (removes water from air in tube) and covered by bung (no air can enter)
- leave for several days then look for changes
- 1 will rust, 2 and 3 wont
35
what conditions are required for rusting
- metal must be iron or an alloy of iron, eg steel
- both water and air
36
how to stop corrosion of iron
barriers:
- grease
- paint
- electroplating (coat in metal)
sacrificial protection/galvanising: coat in zinc - barrier, acts as sacrificial protection if scratched
37
what is sacrificial protection
when a more reactive metal is placed with the iron, meaning it will corrode rather than the iron
38
what is an alloy
a mixture of a metal with another element to disrupt the metal's structure, making it harder
39
what is the alloy bronze made from, what are the uses and why
- copper and tin
- used for statues as it is hard and doesnt corrode
40
what is the alloy brass made from, what are the uses and why
- copper and zinc
- used for musical instruments and door handles as it is malleable
41
what are gold alloys made from, what are the uses and why
- silver, copper, and zinc
- used in jewellery as pure gold is too soft.
42
what are carats? what does 18 carats mean?
measure of the purity of gold
24 means 100% pure, 18 means 75%, etc
43
what are aluminium alloys used for and why
- aeroplane bodies as they are low density
44
what is the alloy steel made from and what are the uses
- iron, specific amounts of carbon, sometimes other metals
- high carbon: making cutting tools as they are very hard
- low carbon: car bodies as it is softer/malleable
- stainless steel, adding chromium and nickel: cutlery, as it is hard and corrosion-resistant
45
issues of steel and how is this solved
- it is al alloy of iron, meaning it can rust
- chromium and nickel added to make stainless steel, which is corrosion resistant
46
what is glass and clay an example of
ceramics
47
how is soda-lime glass made
- mixture of sand, sodium carbonate, and limestone heated in furnace until melted
- solidifies into chosen shape when cooled
48
issues of soda lime glass and alternative
sode lime glass has relatively low MP so has limited uses.
- borosilicate glass has higher MP, useful for objects that require heating eg kitchenware
49
how is borosilicate glass made
- mixture of sand and boron trioxide heated in a furnace until melted
- solidifies into chosen shape when cooled
50
how are clay ceramics made
- found in ground as mineral
- shaped when wet
- heated in furnace to harden
51
what are composites and what properties do they have
- made of one material, the reinforcement, consisting of fibres or fragments of on material, surrounded by a matrix/binder material
- properties of materials within
52
what are carbon fibre composites made from and what are the uses
reinforcement: fibres of carbon
matrix: plastic resin
- used in making cars/aircraft as they are strong and light
53
what is reinforced concrete made from and what are its uses
reinforcement: steel bars
matrix: concrete
- used in making building as it is extremely strong
54
what does a polymers properties depend on and how can they change
- monomer
- conditions used to make the polymer
- change reaction temperature
- change reaction pressure
- change the catalyst
55
how do thermosoftening polymers respond to heat and why
- melt when heated, as intermolecular forces break and polymer strands separate
- reshaped while soft
- solidify when cooled, as intermolecular forces reform
56
how do thermosetting polymers respond to heat and why
do not melt when heated, as strands are held by strong crosslinks
57
uses of ammonia
nitrogen-based fertilisers for farming
58
haber process word equation
nitrogen + hydrogen --(iron catalyst)--> ammonia
59
haber process chemical equation
N2 +3H2 --> 2NH3
60
how are the reactants of the haber process sourced
nitrogen: extracted from the air
hydrogen: reacting methane with steam
61
explain the haber process
- purified nitrogen and hydrogen pass over an iron catalyst at 450 degrees and 200 atmospheres pressure
- some of the n2 and h2 molecules react to form ammonia
- reversible reaction, ammonia breaks back down into nitrogen and hydrogen
- hydrogen cools to liquid and is removed. unused h2 and n2 are then recycled back over catalyst
62
different ways we can change the haber process to maximise yield
lower temp
higher pressure
iron catalyst
63
how can we maximise yield by changing the temperature of the haber process and what are the limits
- forward reaction is exo, so using a cool temp will shift equilibrium to the right, producing more ammonia
- cool temp makes reaction slow, so a 450 degrees is a compromise to get relatively high yield at relatively high rate
64
how can we maximise yield by changing the pressure of the haber process and what are the limits
- high pressure will shift equilibrium to the right, producing more ammonia
- expensive and dangerous to use such high pressures, so 200 atmospheres is a compromise to get relatively high yield safely
65
how does iron catalyst affect the haber process
speeds reaction
does not affect yield
66
what do fertilisers do
replace elements missing elements taken up by plants
67
what are npk fertillisers
contain compounds of nitrogen, phosphorus, and potassium in percentages needed by the plant, improving agricultural productivity
68
how are npk fertilisers produced
variety of raw materials processed together in large industrial facilities to produce exact fertiliser required
69
how are compound of nitrogen produced in npk
main compound is ammonium nitrate
- use haber process to produce ammonia, which can make nitric acid
- react nitric acid with more ammonia to make ammonium nitrate
70
how are compounds of potassium produced in npl
from potassium chloride or potassium sulfate mined from the ground
71
how are compounds of phosphate produced in npk
mined, then treated with following acids to produce many compounds:
- nitric acid and ammonia to produce ammonium phosphate
- sulfuric acid to produce single superphosphate
- phosphoric acid to produce triple superphosphate
72
how are compounds of phosphorus made using nitric acid (for npk)
- rock treated with nitric acid, produces phosphoric acid and calcium nitrate
- phosphoric acid, although containing phosphorus, cannot be added directly to plants, neutralised with ammonia
- ammonium phosphate produced and used
73
how are compounds of phosphorus made using sulfuric acid (for npk)
- rock treated with sulfuric acid, produces single superphosphate, a mixture of calcium phosphate and calcium sulfate
74
how are compounds of phosphorus made using phosphoric acid (for npk)
- rock treated with phosphoric acid, produces triple superphosphate
75
ammonium nitrate fertiliser production in industry vs in a lab
in industry
- concentrated solutions used, dangerous as reaction is very exothermic, heat has to be safely removed
- to produce crystals, heat energy provided from heat removed in exothermic reaction
- continuous process: thousands of kgs produce easily
in lab:
- dilute solutions used to make them safe to work with
- to produce crystals, bunsen burner requires a lot of heat energy
- batch process: can only produce small amounts
