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AQA GCSE - Chemistry - paper 2 > using resources > Flashcards

using resources Flashcards

1
Q

What are ceramics?

A

Ceramics are non-metal solids with high melting points that aren’t made from carbon-based compounds

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2
Q

What are composites?

A

Composites are made of one material embedded in another. Fibres or fragments of a material (reinforcement) are surrounded by a matrix acting as a binder.

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3
Q

Give an example of a composite:

A
  • fibreglass - fibres of glass embedded in a matrix of polymer
  • carbon fibre - have a polymer matrix. Reinforcement is either long chains of carbon or carbon nanotubes
  • Concrete - concrete is made from aggregate embedded in cement
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4
Q

What two things can influence a polymers’ properties?

A
  • how it is made
  • what is is made from
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5
Q

Describe the properties of ceramics:

A

Ceramics include glass and clay ceramics like bricks. They are insulators of hat and electricity, brittle, and stiff

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6
Q

Describe the properties of polymers:

A

Polymers are insulators of heat and electricity. They can be flexible and are easily moulded. Polymers have many applications including clothing

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7
Q

Describe the properties of composites:

A

The properties of composites depend on the matrix/binder and the reinforcement used. This means they have many uses.

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8
Q

Describe the properties of metals:

A

Metals are malleable, good conductors of heat/electricity, ductile, shiny and stiff. Metals have several uses like cutlery

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9
Q

Why do we use alloys?

A

Metals do not always have the necessary properties, so you can mix them to form alloys with the desired properties.

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10
Q

what is the equation for rust?

A

iron + oxygen + water –> hydrated iron(III) oxide

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11
Q

What two things are needed for iron to rust?

A

Air and Water

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12
Q

What two ways can we prevent rust?

A
  • coat the iron in a barrier
  • sacrificial method
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13
Q

Describe coating iron in a barrier to prevent rust:

A

This is covering the iron in a substance to prevent it from rusting. For example:
- painting/coating with plastic
- electroplating
- oiling/greasing

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14
Q

Describe the sacrificial method to prevent iron rusting?

A

This involves placing a more reactive metal with the iron, so the water and oxygen react with that rather than the iron. For example:
- placing zinc with the iron
- placing magnesium with the iron

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15
Q

Give an example where you coat the iron and use the sacrificial method at once:

A

An object can be galvanised by spraying it with a coating of zinc. The zinc layer is firstly protective, but it scratched, the zinc around the scratch works as a sacrificial metal

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16
Q

what are finite resources?

A

Resources that cannot be replaced as quickly as they are being used

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17
Q

what are renewable resources?

A

Resources that can be replaced as quickly as we use them

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18
Q

what is sustainable development?

A

Meeting our needs without preventing future generations from meeting theirs

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19
Q

What is the issue with extracting finite resources?

A
  • you have to balance social, economic, and environmental effects
20
Q

How is chemistry improving sustainability?

A

Chemistry can develop and adapt processes to make it more sustainable

21
Q

What is phytomining?

A

growing plants in soil that contains copper. The plants cannot use or get rid of copper so it gradually builds up in the leaves. The plants can be harvested and burned in a furnace. The ash contains soluble copper compounds from which copper can be extracted by electrolysis or displacement using iron

22
Q

what is bioleaching?

A

Bacteria are used to convert copper compounds in the ore into soluble copper compounds, separating out the copper from the ore in the process. The leachate (solution produced) contains copper ions, which can be extracted.

23
Q

Why is recycling metals important?

A
  • mining an extracting metals takes a lot of energy, which comes from burning fossil fuels
  • recycling metals often uses less energy, conserves the finite amount, and cuts down on the amount of waste being sent to landfill
24
Q

How can glass be recycled?

A
  • glass bottles can be reused without reshaping
  • other forms of glass cannot be reused so the are separated by colour and chemical composition
  • the glass can be crushed, melted and reshaped for use in glass products like bottles or jars
25
Q

What does a life cycle assessment (LCA) do?

A

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

26
Q

What are the 4 stages of a life cycle assessment?

A

1) getting the raw materials
2) manufacture and packaging
3) usage of the product
4) product disposal

27
Q

What are the problems with life cycle assessments?

A
  • the use of energy, some natural resources and the amount of certain types of waste can easily be quantified, but it is difficult to apply this value to the long term effect
  • LCAs can be biased
  • selective LCAs only show some impacts of the product, leading to false positive advertising
28
Q

what is potable water?

A

Water is essential for life. Water that is safe for humans to drink is called potable water. Potable water is not pure water because it almost always contains dissolved impurities.

29
Q

what does water need to be so it is potable?

A

For water to be potable, it must have sufficiently low levels of dissolved salts and microbes. This is because:
- dissolved salts can sometimes be harmful for humans
- microbes can cause illnesses

30
Q

How is potable water produced?

A

The methods used to make water potable depend on where you live. Most potable water in the UK is produced from naturally occurring fresh water by:
- passing the water through filter beds to remove insoluble particles
- sterilising the water to kill microbes

31
Q

What is desalination?

A

The removal of salt from water. This is an energy-intensive process

32
Q

How can desalination be done?

A

Desalination can be done by distillation and by reverse osmosis

33
Q

explain the two methods of desalination:

A

distillation - Sea water is heated until it boils. The salt remains in the liquid, and the steam is pure water. The steam is cooled and condensed to make potable water.
reverse osmosis - Water is put under high pressure and passed through a membrane which has tiny pores (holes) in it. The pores allow water molecules through, but prevent most ions and molecules from passing through.

34
Q

what pollutants could be present in waste water?

A
  • human waste contains harmful bacteria and high levels of nitrogen compounds which can harm aquatic ecosystems
  • industrial waste water may contain harmful chemicals such as toxic metal compounds
  • agricultural waste water may contain fertilisers or pesticides which can disrupt sensitive ecosystems
35
Q

what are the steps of treating sewage?

A
  • screening and grit removal to remove large particles
  • sedimentation allows tiny particles to settle out from still water, which produces sewage sludge and effluent (the liquid which remains on top)
  • the sewage sludge is digested anaerobically by specific bacteria
  • the effluent is treated with aerobic bacteria to reduce the volume of solid waste
36
Q

What is the Haber process?

A

It is the industrial process used to produce ammonia, which is used in fertilisers

37
Q

what are the steps of the Haber process?

A

1) nitrogen (from the air) and hydrogen (from natural gas) are pumped through pipes
2) the pressure of the mixture is increased to 200 atmospheres
3) the pressurised gases are heated to 450°C and passed through a tank containing an iron
catalyst
4) the reaction is cooled so that the ammonia liquefies and can be collected
5) unreacted nitrogen and hydrogen are
recycled

38
Q

What are fertilisers?

A

fertilisers are mixtures that provide mineral ions to grow healthy plants. As plants grow, they absorb mineral ions from the water in the soil through their root hair cells.

39
Q

what do fertilisers actually contain?

A

Fertilisers may contain nitrogen, phosphorus and potassium compounds to promote plant growth. NPK fertilisers are fertilisers which supply all 3 of these.

40
Q

why do fertilisers need to be soluble?

A

so they can be absorbed by the root hair cells

41
Q

What is the compromise made in making ammonia?

A

The temperature is 450 degrees, because it is halfway between maximum yield and speed of reaction because it is a reversible reaction

42
Q

How is ammonia reacted to make nitric acid

A

it is reacted with oxygen and water in a series of reactions

43
Q

How are ammonia salts made?

A

reacting ammonia with an acid

44
Q

Why do we react ammonia and nitric acid?

A

It produces ammonia nitrate which is good for farming as it has nitrogen from two sources

45
Q

How is the Haber process carried out in industry?

A

The reaction is done in giant vats, at high concentrations, meaning it is a very large exothermic reaction. The heat is used to evaporate water from the mixture to make it a very concentrated ammonia nitrate product

46
Q

How is the Haber process carried out in the lab?

A

The reaction is carried out on a smaller scale through titration and crystallisation. The reactants are at a smaller concentration so less heat is produced, making it safer to carry out.

47
Q

where are phosphate and potassium sourced from?

A

Potassium chloride and potassium sulphate can be mined and used as a source of potassium. Phosphate rock is also mine but the salts are insoluble, so the plant cannot use them. Reacting phosphate rock with an acid produces soluble phosphates, which the plant can use

AQA GCSE - Chemistry - paper 2 (5 decks)

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