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CHEMISTRY > C14 > Flashcards

C14 Flashcards

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1
Q

what are the 2 main ways to class resources

A

finite and infinite (renewable)

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2
Q

define finite resources

A

a resource which will eventually run out

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3
Q

define renewable resource

A

a resource which will never run out because it can be replenished at the rate it is used up

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4
Q

what are some natural resources which are used and the alternate synthetic product made

A

wool - clothes - acrylic fibre
cotton - clothes - polyester
silk - clothes - nylon
linseed oil - paint - acrylic resin
rubber - tyres - synthetic polymers
wood - construction - PVC

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5
Q

what does natural water contain

A
  • insoluble impurities
  • soluble impurities
  • biological impurities
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6
Q

what is potable water

A

water that is safe to drink

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7
Q

how do methods of collecting potable water vary in each country

A

it depends on the available supplies of water and the local conditions

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8
Q

how does the UK gather potable water

A

rain water provides water with low levels of dissolved substances which is then collected into lakes and rivers

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9
Q

how is most potable water produced

A
  • choosing an appropriate source of fresh water
  • passing the water through filter beds
  • steralising
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10
Q

what are some sterilising agents used in potable water

A
  • chlorine
  • UV light
  • ozone
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11
Q

what is the water treatment process of fresh sources of potable water

A
  1. filter beds remove large objects
  2. sand and soil becomes settled and fall to the bottom of the settlement tank
  3. aluminium sulphate and lime are added which causes small particles of dirt to clump together and fall to the ground. this forms a sludge which is then taken to landfill
  4. the water is passed through a filter of fine sand so any remaining mud or grit is removed
  5. the water is sterilised by chlorine
  6. the pH of the water is checked and corrected to it’s neutralised
  7. the water is stored in large tanks till needed
  8. the water is pumped to where it is needed
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12
Q

what is pure water

A

water which only contains water particles

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13
Q

how can water be purified

A

by desalinisation

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14
Q

why is pure water used

A

it is used for experiments in labs by chemists

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15
Q

is pure water safe to drink

A

no, as our bodies will start to become deficient in some ions

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16
Q

what is desalinisation

A

the process of removing salt from sea water

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17
Q

what is the problem with desalinisation

A

it uses a vast amount of energy

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18
Q

what are the 2 methods of desalinisation

A
  • reverse osmosis
  • distillation
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19
Q

what is reverse osmosis

A

where sea water is passed through a membrane. The membrane has small pores which is big enough to allow water to pass but the salt is too big and so can not pass through the membrane and so gets trapped.

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20
Q

what are the advantages and disadvantages of reverse osmosis

A
  • most minerals and ions can not pass through the small pores
  • expensive membranes are required and produces large amounts of waste water
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21
Q

why is there large amounts of waste water

A

due to urban lifestyles

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22
Q

what happens to the waste water before being released into the environment

A

it is treated

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23
Q

what does sewage and agricultural waste water require removal of

A
  • organic matter
  • harmful microbes
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24
Q

what does industrial waste water require removal of

A
  • organic matter
  • harmful chemicals
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25
Q

what are the steps to sewage treatment

A
  1. sewage arrives at the pumping station
  2. the sewage is screened to remove large solid objects
  3. Primary treatment - solid sediments settle down forming a sludge at the bottom of the tank. this sludge is pushed to another area. the effluent at the top is moved to the next area
  4. secondary treatment - useful bacteria feed on the remaining organic matter and other harmful organisms, breaking them down aerobically.
  5. final treatment - the useful bacteria settle down at the bottom of the tank as sediment . water is safe but can be filtered one more time using chlorine.
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26
Q

how can sewage sludge be treated

A
  • it can be separated and dried off to be used as fertiliser
  • it can be digested anaerobically by microorganisms
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27
Q

what is an ore

A

a naturally occurring rock where metal or metal compounds are concentrated enough to be economical to extract

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28
Q

what properties of copper make it useful

A
  • ductile - useful for wiring
  • good conductor of heat and electricity
  • unreactive - does not react with water
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29
Q

what are the 2 main ways to extract copper

A
  • using sulphuric acid
  • smelting and then electrolysis
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30
Q

how does sulphuric acid work when extracting copper

A

sulphuric acid is added to make copper sulphate solution, before extracting the copper metal. Iron scraps are added to the copper sulphate. The Iron displaces the copper in the copper sulphate.

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31
Q

how doe smelting work when extracting copper

A

copper ore is heated to a high temperature in a furnace with air to make impure copper. The impure copper is used as the positive electrode in electrolysis cells to make pure copper. electrolysis is used to make copper pure.

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32
Q

what is the problem currently with mining copper

A

we are running out of copper rich ores

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33
Q

what are the 2 ways to class ores

A
  • low-grade ores
  • high-grade ores
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34
Q

what are the 2 ways to extract copper from low-grade ores

A

bioleaching and phytomining

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35
Q

how does Phytomining work

A

plants are grown in soil which contain low-grade copper ore. the plants absorb the copper ions. The plants are burnt and the copper is extracted from the copper compounds in the ashes. the copper ions are dissolved into sulfuric acid making copper sulfate. Displacement by Iron scraps and electrolysis makes pure iron.

36
Q

how does bioleaching work

A

bacteria feed on the low-grade copper ore. through chemical and biological processes a solution of copper ions called a leachate is formed. The copper ion solution (leachate) is displaced by iron scraps and electrolysis is used to extract the copper from the leachate.

37
Q

what is the disadvantage of bioleaching

A

the process is very slow. it can take years to just extract 50% of the ore.

38
Q

what are the stages of a producst life cycle

A

1- raw material
2- manufacture
3- use
4- disposal

39
Q

what is the first stage of completing a life cycle assesment of a product

A

if it is renewable, how the raw materials are extracted, do they need to be processed,

40
Q

what is the second stage of completing a life cycle assessment of a product

A

are any pollutants formed like gas, does it require a lot of energy, are there any waste products and if fo how are they disposed of

41
Q

what is the 3rd stage of completing a life cyce assessment of a product

A

how long can they product be used for, how many times can it be used over, does the usage of the product harm the environment

42
Q

what is the 4th stage of completing a life cycle assessment of a product

A

how are the products disposed of, can they be recycled, how are the products transported

43
Q

what is the 1st stage of a lifecycle assessment of a plastic bag

A
  • made up of crude oil which is a finite resource
  • ## crude oil is processed through fractional distillatin which requires alot of energy
44
Q

what is the 2nd stage of the life cycle assesment of a plastic bag

A
  • involves carcking and polymeristaion
  • process rquires heating which uses a lot of energy
45
Q

what is the 3rd stage of a life cycle assessment of plastic bag

A
  • can be used multiple times
46
Q

what is the 4th stage of a life cycle assessment of a plastic bag

A
  • can be recycled
  • if taken to a landfill it is not biodegradable and so takes up space in landfill and can be eaten by animals
  • incenerating the products can release toxic gases into the atmosphere
47
Q

what is the 1st stage of a lifecycle assessment of a paper bag

A
  • obtained from trees but can be replanted
  • habitats are destroyed when trees are cut down
  • pollution is caused due to oil being used as fuel for transportation
48
Q

what is the 2nd stage of a lifecycle assessment of a paper bag

A
  • uses lots of water and some chemicals which could harm the environment
  • transportation uses oil and so pollutes the air
49
Q

what is the 3rd stage of a lifecycle assessment of a paper bag

A
  • reusable butis mostly used only once
50
Q

what is the 4th stage of a lifecycle assessment of using a paper bag

A
  • can be recycled
  • biodegradable
  • non-toxic
51
Q

what are the aims of the reduce, reuse and recycle campaigns

A
  • reduce the use of limited resources
  • reduce the use of our energy
  • reduce the waste we produce
52
Q

why is the recylcing aluminium important

A
  • to protect the Earths’ reserve of aluminium
  • getting aluminium requires the use of electrolysis which requires a lot of energy which is the recycling of aluminium is important as recycling saves energy (95% energy saved) and thus money as recycling does not require the use of electrolysis
53
Q

how is aluminium recycled

A

1- aluminium is fed to a conveyer
2- aluminium is shredded
3- goes to the decoater
4- melted in furnaces
5- goes to tilting holding furnace
6- goes throught the filtration unit
7- becomes solidified in the direct chill casting unit
8- shredded again into ingots

54
Q

how is recycling iron and steel sustainable

A
  • tin cans and some car parts can get melted down and reformed to ingots
  • this saves 50% of the energy
  • 50% less pollutants are made by recycling iron rather than collecting iron as it uses 50% less fossil fuels
55
Q

why is recycling copper harder than recycling other stuff

A

as copper is usually in mixed with other metals to form an alloy which means you have to seperate it the copper first then melt it down to form it to ingots. however copper wires are pure so they can be melted down straight away to be formed into ingots

56
Q

how have humans impacted the natural cycling of nitrogen

A
  • when plants grow they take in nitrogen in the soil and when they die they decompose allowing the nitrogen to go back into the soil however farmers collect the crops so the nitrogne can’t go back into the soil which is why farmers need to use fertillisers
57
Q

what is the 1st step of the haber process

A

nitrogen gas is collected from the air through fractional distillation ( -200 degrees celcius is the temp required for nitrogen to be a liquid)
hydrogen is collected from reacting mthane and stem to form hydrogen and CO2

58
Q

what is the 2nd stage of the haber process

A

the nitrogen and hydrogen are purified and passed over an iron catalyst and at high temperatures ( 400 degrees celcius) and high pressures ( 200 atmospheres). which gives the reversible reaction:
N2 + 3 H2 <—> 2 NH3
nitrogen + hydrogen <—> ammonia

59
Q

what happens at equilibrium

A

the amount of products and reactants wont change

60
Q

what is dynamic equilibrium

A

when the forward reaction = the backward reaction

61
Q

in the haber process which reaction is endo and exothermic

A

forward reaction is exothermic and backward reaction is endothermic

62
Q

how does temperature affect the haber process

A

lower temps means higher yield of ammonia but slower reaction

63
Q

in the haber process which reaction produces more moles of gas

A

the forward reaction produces 2 moles of ammonia whil the backwards reaction produces 4 moles

64
Q

how does pressure affect the haber process

A

high pressures would lead to a higher yield os ammonia but can be dangerous as hydrogen is explosive

65
Q

why is an iron catalyst used in the haber process

A

to speed up the reaction (it does not effect the yield)

66
Q

what is corrosion

A

a chemical reaction between the metal and the substances in the environment

67
Q

what is the corrosion of iron called

A

rusting

68
Q

what can corrosion do to a metal

A
  • affect the strength
  • affect the look
  • or destroy the metal
69
Q

why does aluminium not rust

A

most aluminium metals have a protective oxide layer which protects it from corrosion

70
Q

how do you prevent rust

A

air and water is needed for iron to rust. which is why if your wrap/coat iron in oil, plastic or a less/mor reactive metal the iron will not rust

71
Q

owhy is more reactive metals used to coat iron

A

as when the coating get scratched the iron does not rust

72
Q

how is iron coated it a more reactive metal

A

the iron is galvanised which allows zinc to be coated in the iron

73
Q

how does zinc stop rusting

A

zinc is more reactive than iron so it has a stronger tendancy to tun into positive ions by giving away electrons. as the zinc atoms lose electrons they become oxidised so any water or oxygen reacts with zinc rather than the iron. this is called sacrifical protection which sacrifices the zinc to save the iron

74
Q

how can you setup a test to test that oxygen and water is needed for rusting

A

1- setup 3 test tubes
2- test tube A place calcium chloride chloride to remove any water then place some cotton wool and then the iron object.
3- test tube B place nail can cover with boiling water and then a layer of water
4- test tube c place nail and add some water ontop so that the tops of the nail is exposed to the air

75
Q

what is copper made up of

A

copper and tin

76
Q

why is bronze useful

A

it is highy resistant to corrosion

77
Q

what is brass made up of

A

copper and zinc

78
Q

why is brass useful

A

it is harder than copper and can be shaped into sheets to be used for musical instruments or taps

79
Q

why are aluminium alloys good

A

it has a low density (cause of the aluminium) which makes it lightweight but really strong so it is used in aircraft

80
Q

what is gold alloys normally made up of

A

gold ofc and copper when it’s used to make jewellary. gold purity is measured in carat (highest is 24 carat)

81
Q

what is steel made up of and why is it useful

A

it is mde up of iron and carbon but other metals can also be added to have steel with different properties

82
Q

what is the simplest form of steel

A

carbon steels

83
Q

why is carbon steel used

A

it is the cheapes steel to make and by controlling the carbon content the steel can be made stronger if more carbon is added but it becomes more brittle. on the other hand lower carbon content means a softer steel but it is less brittle

84
Q

what are the cons of using alloy steels

A
  • more expensive
85
Q

what are nickel steels used for

A

bicyle chains, long-span bridges and military armour plating as it is very resistant to stretching forces

86
Q

what is tungsten steel used for

A

high speed tool bits as it spins very fast so it becomes hot and tungsten steel is very resistant to high temperatures

87
Q

what is chromium-nickel steel used for

A

it is very hard and it is strong which makes it very useful but it does not rust which is why it is used for cooking utensils and cutlery
it is also used in chemical plants as it is used in reaction vessels which is why chemical plants are expensive to set up

CHEMISTRY (12 decks)

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