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Chemistry - using resources Flashcards

1
Q

What are ceramics

A

No-metal solids with high melting points that aren’t made from carbon-based compounds. Some ceramics can be made from clay

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2
Q

What is clay

A

A soft material when dug up out the ground - can be moulded into different shapes

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3
Q

How does clay form ceramics

A

When it’s fired at high temperatures it hardens to form a clay ceramic

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4
Q

Characteristics of glass

A

Example of ceramic
generally transparent
can be moulded when hot
can be brittle when thin

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5
Q

How is soda-lime glass made

A

Made by heating a mixture of limestone, sand and sodium carbonate until it melts. When the mixture cools it comes out as glass

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6
Q

What are composites

A

Usually made of one material embedded in another. The properties of a composite depend on the material its made from

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7
Q

Borosilicate glass compared to soda - lime glass

A

Has a higher boiling point - useful for objects that require heating eg. kitchenware or labware

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8
Q

How is boron silicate glass made

A

Made by melting a mixture of sand and boron trioxide

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9
Q

Features of composities

A
  • Reinforcements which consits of fibres or fragments of one material
  • Matrix or binder surrounds the reinforcement
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10
Q

Carbon fire composites

A

Have a polymer matrix
Reinforcement made from either long chains of carbon atoms bonded together or from carbon nanotubes
Very strong and light - used in aerospace and sports car manufacturing

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11
Q

Concrete

A

Made from aggregate (a mixture of sand and gravel)
embedded in cement
Very strong - ideal for building houses

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12
Q

Wood

A
  • natural composite of cellulose fibres
  • organic polymer matrix
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13
Q

Fibreglass

A
  • fibres of glass
  • matrix made of polymer
  • low density
  • very strong
  • used for skis, boats and surfboards
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14
Q

What do the properties of polymers depend on

A
  • The monomer (what its made from)
  • The conditions used to make the polymer (how its made)
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15
Q

Thermosoftening polymers

A

Melt when we heat them
Can be reshaped while their soft
Go back to a solid when we cool them back down

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16
Q

How could you change the properties of polymers

A
  • the reaction pressure
  • the reaction temperature
  • the catalyst
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17
Q

Why can thermosoftening polymers be easily melted

A

They contain individual polymer chains entwined together with weak forces between the chains.

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18
Q

Thermosetting polymers

A
  • do not melt when we heat them
  • strong, hard and rigid
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19
Q

Why do thermosetting polymers not melt

A

Contain monomers that can form cross links between the polymer chains, holding the chains together in a solid structure.

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20
Q

Definition of corrosion

A

The destruction of materials by chemical reactions with substances in the environment

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21
Q

What does rusting only apply to

A

Iron and alloys of iron such as steel

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22
Q

What is needed for iron to rust

A

Iron needs to be in contact with both oxygen and water which are present in air

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23
Q

When does aluminium corrode

A

Aluminium corrodes when exposed to air

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24
Q

Difference between corrosion of iron and corrosion of aluminium

A

Unlike iron objects, things made from aluminium aren’t completely destroyed by corrosion. This is because aluminium oxide doesn’t flake away and instead forms a protective layer that sticks to the aluminium and stops and further reaction taking place

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25
Q

Describe an experiment that shows both oxygen and water are needed for iron to rust

A
  • If you put an iron nail in a boiling tube with just water it won’t rust (the water is boiled to remove oxygen and oil is used to stop any oil getting in it)
  • If you put an iron nail in a boiling tube with just air it won’t rust (calcium chloride can be used to absorb any water from the air)
  • However if you put an iron nail in a boiling tube with air and water it will rust
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26
Q

Ways to prevent rusting

A
  • coat iron with a barrier to keep out the water and oxygen eg. paint/coat with plastic, electroplating, oiling/greasing
  • sacrificial method
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27
Q

Sacrifical method of preventing rusting

A

Involves placing a more reactive metal such as zinc or magnesium with the iron. Water and oxygen then react with the sacrificial metal instead of the iron.

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28
Q

Where do natural resources come from

A

Earth, sea and air

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29
Q

Natural resources meaning

A

Form without human input

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30
Q

Renewable resources

A

Reform at a similar rate to, or faster than, we use them.

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31
Q

Finite resources

A

Aren’t formed quickly enough to be considered replaceable.

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32
Q

Examples of finite resources

A
  • Fossil fuels
  • Nuclear fuels (uranium and plutonium)
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33
Q

After being extracted what happens to many finite resources and examples

A

they undergo man-made processes to provide fuels and materials necessary for modern life. Eg. fractional distillation is used to produce usable products such as petrol from crude oil and metal ores are reduced to produce a pure metal.

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34
Q

Risks of extracting finite resources

A
  • Uses loads of energy
  • Scars the landscape
  • Produces lots of waste and destroys habitat
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35
Q

Sustainable development

A

Development that meets the needs of current generations without compromising the ability of future generations to meet their own needs

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36
Q

Way of reducing the use of finite resources

A
  • Using them less
  • Chemists can develop and adapt processes that use lower amounts of finite resources
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37
Q

Way to improve coppers sustainability

A

Extracting it from low-grade ores (ores without much copper in).
We can do this by Bioleaching or Phytomining

38
Q

Bioleaching

A

Bacteria are used to convert metal compounds into soluble metal compounds separating out the metal from the ore in the process. Produces leachate solutions that contain metal compounds.

39
Q

Phytomining

A

Uses plants to absorb metal compounds from the soil. The plants air harvested and then burned to produce ash that contains the metal compound.

40
Q

Disadvantage of bioleaching or phytomining

A

They are slow

41
Q

Why is recycling metals important

A

Mining and extracting metals takes lots of energy most of ewhich come from burning fossil fuels
Recycling metals uses much less energy as it conserves the finite amount of each metal and cuts down on the amount of waste getting sent to landfill

42
Q

How are metals usually recycled

A

By melting them and then casting them into the shape of the new product

43
Q

How can glass recycling help sustainability

A

Reduces the amount of energy needed to make new glass products, and also the amount of waste created when used glass is thrown away.

44
Q

How can glass be recycled

A

Glass is separated by colour and chemical composition before being recycled
The glass is crushed then melted to be reshaped for use in glass products such as bottles or jars.

45
Q

Life cycle assessments

A

Looks at every stage of a products life to show the impact it would have on the environment

46
Q

Issues with getting raw materials

A
  • Extracting raw materials needed for a product can damage the local environment
  • Raw materials often need to be processed to extract the desired materials and this often needs large amounts of energy
47
Q

Issues with manufacturing and packaging

A
  • Manufacturing products and their packaging can often take up a lot of energy resources and can cause a lot of pollution
  • Waste products and disposing of them
48
Q

Issues with using the product

A

Can damage the environment
How long a product is used for or how many uses - products that need lots of energy to produce but are used for ages mean less waste in the long run

49
Q

Issues with product disposal

A

Products are often disposed of in landfill sites - takes up space and pollutes land and water
Energy is used to transport waste to landfill, which causes pollutants to be released into the atmosphere
Products might be incinerated which causes air pollution

50
Q

Raw materials of plastic bag compared to paper bag

A

Plastic bag - Crude oil
Paper bag - Timber

51
Q

Manufacturing and packaging of plastic bag

A

Plastic bag - Compounds extracted from crude oil by fractional distillation. Waste is reduced as other fractions of crude oil have other uses.
Paper bag - Pulped timber is processed using lots of energy. Lots of waste is made

52
Q

Using plastic bag vs paper bag

A

Plastic bags - Can be reused and be used for other things as well as shopping like bin liners
Paper bags - Usually only used once

53
Q

Plastic vs paper bag disposal

A

Plastic bag - recyclable but not biodegradable so will take up space in landfill
Paper bag - Biodegradable, non toxic and can be recycled.

54
Q

Problems with life cycle assessments

A

The effect of some pollutants is hard to give a numerical value
Producing an LCA is not an objective method as it takes into account the values of the person carrying out the assessment - can be bias
Can be used for positive advertising

55
Q

Potable water

A

Water that is naturally safe for humans to drink - levels of dissolved water aren’t to high and no bacteria or microbes in it

56
Q

Pure water

A

Water. that only contains H20 molecules

57
Q

Way potable water is produced in the UK

A

Rainwater collects in the ground in aquifers , and in lakes rivers and reservoirs which are all good sources of fresh water. Then pass water through filter beds. then sterilise using chlorine

58
Q

What do we use filter beds for

A

To remove materials such as leaves and suspended particles.

59
Q

Why do we sterilize the water

A

To kill microbes

60
Q

Why do we use rainwater as a source of water

A

It has very low levels of dissolved minerals

61
Q

How do very dry counties get water

A

Use sea water. Potable water is produced by desalination. Use distillation or reverse osmosis. Reverse osmosis is whereby salty water is passed through a membrane that only allows water molecules to pass through.

62
Q

What does desalination do

A

Reduces the levels of dissolved minerals down to an acceptable level for potable water

63
Q

Problems of distillation and reverse osmosis

A

They need loads of energy, so they’re really expensive.

64
Q

Why does sewage have to be treated

A

To remove any organic matter and harmful microbes before it can be put back into fresh water sources

65
Q

First step of sewage treatment

A

Screening - this involves removing any large bits of materials well as any grit

66
Q

Second step of sewage treatment

A

Stands in settlement tank and undergoes sedimentation - the heavier suspended solids sink to the bottom to produce sludge and lighter effluent floats to the top

67
Q

Third step of sewage treatment

A

The effluent in the settlement tank is removed and treated by biological aerobic digestion. This is when air is pumped through the water to encourage aerobic bacteria to break down any organic matter.

68
Q

Fourth step of sewage treatment

A

Sludge from the bottom, of the settlement tank is removed into large tanks. gets broken down by anaerobic digestion. Releases methane in the process.

69
Q

What are needed to make ammonia

A

Nitrgogen and Hydrogen

70
Q

Reaction of ammonia

A

N2 + 3h2 <———> 2NH3 (+heat)

71
Q

Why is the harbour process well suited for an industrial scale

A

Reactants aren’t too difficult or expensive to obtain

72
Q

How is nitrogen obtained

A

From the air

73
Q

How is hydrogen obtained

A

From reacting methane with steam to formn hydrogen and co2

74
Q

What catalyst is used for the harbour process

A

Iron

75
Q

Conditions for harbour process

A
  • High temp (450 degrees)
  • High pressure (200 atmospheres)
76
Q

In the harbour process what state is the ammonia

A

Original formed as a gas but as it cools in the condenser it liquifies and is removed.

77
Q

Why is temp compromised

A

The forward reaction in the Harbour process is exothermic which means increasing temp will move the equilibrium the wrong way - towards nitrogen and hydrogen. Yield of ammonia would be greater at lower temps.
- However 450 degrees is used so that there is another kinetic energy to overcome the activation energy

78
Q

Why is pressure compromised

A

Higher pressures move the position of equilibrium towards the products as this is the side with the fewer moles. So increasing pressure maximises the percentage yield. However it cannot be too high as the process could be too expensive or dangerous to build and maintain.

79
Q

What do fertilisers allow

A

Allow us to keep growing crops on the same land every year

80
Q

What compounds do NPK fertilisers contain

A

Compounds of phosphorous, nitrogen, and potassium

81
Q

Why are formulated fertilisers better

A
  • widely available
  • easier to use- don’t smell
  • have just enough nutrient so more crops can be grown.
82
Q

What do fertilisers do

A

They replace missing elements or provide more of them

83
Q

How do phosphorus, nitrogen and potassium

A

They help to increase crop yield as the crops can grow faster and bigger. T

84
Q

How are nitrogen containing compounds formed

A

Ammonia can be reacted with oxygen and water in a series of reactions to form nitric acid
Ammonia and nitric acid can react together to form ammonia nitrate which is especially good in fertilisers

85
Q

How is potassium sourced

A

Potassium chloride and sulphate can be mined and used as a source of potassium

86
Q

How is phosphate sourced

A

Phosphate rock is mined however because the phosphate salts in the rock are insoluble, plants cant use them as nutrients.

87
Q

How to produce soluble phosphates

A

Reacting phosphate rock with :different types of acid

88
Q

Single superphosphate

A

Sulphuric acid + phosphate rock —–> calcium sulphate + calcium phosphate

89
Q

Triple superphosphate

A

Phosphate rock + phosphuric acid —–> calcium phosphate

90
Q

What does phosphate rock and nitric acid produce

A

Phosphate acid and calcium nitrate

91
Q
A

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