C14 Flashcards

1
Q

What is water distillation?

A

A seperation technique which involves a solution (salt water) being heated so that the solvent evaporates before being cooled to form a pure liquid (water).

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2
Q

What is desalination?

A

The process by which salt is removed from seawater in order to make drinking water

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3
Q

What are the 2 main methods of desalination?

A

Reverse osmosis and distillation

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4
Q

What is another word for distillation?

A

Thermal desalination

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5
Q

Why is desalination most commonly used in the Middle East?

A
  • many of the countries are quite wealthy
  • rainfall is low
  • many of the countries have coastlines
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6
Q

What is reverse osmosis?

A

Reverse Osmosis is a method that is used to remove a large quantity of contaminants from water by pushing the water under pressure through a semi-permeable membrane.

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7
Q

Advantages of thermal desalination

A
  • improves water quality
  • kills harmful microbes in the water
  • removes all impurities
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8
Q

Disadvantages of distillation

A
  • heating uses a lot of energy
  • energy may come from non-renewable sources
  • expensive
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9
Q

Advantages of reverse osmosis

A
  • no heating involved
  • less energy required
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10
Q

Disadvantages of reverse osmosis

A
  • need to pressurise water
  • corrosion of pumps due to salty water
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11
Q

What are the 4 steps involved in treating waste water?

A

Screening, Primary Treatment, Secondary Treatment, Final Treatment

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12
Q

What is screening?

A

The waste water is passed through a metal grid which removes large objects such as branches

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13
Q

What is primary treatment?

A

Solids are allowed to settle out from the mixture, where large paddles push it to the centre to be piped off for further treatment

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14
Q

What happens during primary treatment?

A

Solids are allowed to settle out from the mixture, where large paddles push it to the centre to be piped off for further treatment

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15
Q

What happens during secondary treatment?

A

Bacteria are released in the liquid where they aerobically break down harmful micro-organisms and any other organic material. Air is bubbled through the liquid.

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16
Q

What happens during final treatment?

A

The bacteria are allowed to settle and are recycled or disposed with the solids

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17
Q

In waste water treatment, what happens to the solids (sludge)?

A

It is anaerobically digested by bacteria and then used as fertiliser/fuel or sent to landfill

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18
Q

What are the 2 main methods used to obtain copper from its ore?

A
  • Smelting
  • Sulfuric acid used to produce coper sulfate before extracting copper metal
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19
Q

What process is used to purify the impure copper extracted by smelting?

A

Electrolysis

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20
Q

How can copper be extracted from copper sulfate solution?

A

By adding iron which will displace copper from the solution

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21
Q

What is malachite?

A

A type of copper ore

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22
Q

What method is used 80% of the time to extract copper from malachite?

A

Smelting

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23
Q

Why is smelting bad?

A

Requires a lot of energy and emits Co2 and So4

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24
Q

What is phytomining?

A

Where plants are grown on low-grade copper ore which absorb copper ions. They are burnt; and the ash is reacted with sulphuric acid to form a leachate of copper sulphate, from which copper is obtained by displacement or electrolysis

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25
Q

What is bioleaching?

A

Where bacteria feed on low grade copper ore and produce a solution of copper ions called the leachate. Copper can be obtained from this by displacement or electrolysis

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26
Q

Why can copper be ocassionally found native?

A

Copper is an unreactive metal – it reacts only slowly with the atmosphere.

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27
Q

Why are methods like phytomining becoming increasingly popular?

A

It is potentially the least harmful method because it uses naturally occurring organisms and preserves the environment in a more natural state.

28
Q

What is a life cycle assessment?

A

A method to analyse the environmental impact and the water and energy usage of a product over its lifetime

29
Q

What are the 5 stages in an LCA?

A

RAW MATERIAL - manufacturing - USE/REUSE - maintenance - recycle

30
Q

Why is recycling aluminium important?

A

It saves 95% of energy compared to producing it

31
Q

Why might LCA’s be totally objective?

A

Assigning the numerical values of environmental aspects is subjective as it requires judgements such as the effect of pollutants.

32
Q

Why are LCA’s carried out on new products?

A

LCA is carried out on new products to assess the environmental impact of the products, process or services and if it is sustainable.

33
Q

What do LCA’s not take into account when comparing products?

A

Differences in cost or performance

34
Q

What is the aim of “reduce, reuse and recycle” campaigns?

A
  • to reduce our use of energy
  • to limit the waste we produce
  • to limit the use of finite resources
35
Q

Why is recycling copper more difficult than other metals?

A

It is usually an alloy and therefore purification is required

36
Q

Why is recycling iron + steel important?

A

Because no fossil fuels need to be burned and 50% less energy is used compared to production.

37
Q

What consumes most of the energy in the production of steel from iron ore?

A

Burning fossil fuels such as natural gas to heat the air entering a blast furnace

38
Q

What do we call products that don’t affect the atmospheric carbon dioxide concentration?

A

Carbon-neutral

39
Q

What toxic gas is produced when sulfur is burned?

A

Sulfur dioxide

40
Q

Which source of potable water is the most expensive to treat?

A

Sea/salt water

41
Q

Which source of potable water is the easiest to treat?

A

Fresh water

42
Q

3 sources that potable water can be obtained from

A
  • fresh water
  • seawater
  • waste water
43
Q

Main sources of waste water

A
  • Domestic
  • Industrial
  • Agriculture
44
Q

Which product of sewage sedimentation is anaerobically digested by bacteria?

A

sludge

45
Q

If materials are not reused or recycled, where do they accumulate?

A

If materials are not reused or recycled, where do they accumulate?

46
Q

What are the steps involved in recycling glass?

A
  • sort
  • crush
  • melt
  • reshape
47
Q

What stages are involved in the processing of glass for it to be converted into other glass products?

A
  1. the colour is sorted by colour and chemical
  2. glass crushed in small pieces
  3. glass melted
  4. reshaped in new product
48
Q

Disadvatanges of bioleaching

A
  • Slow
49
Q

Why are copper-rich ores in short supply?

A

Due to historical overexploitation

50
Q

What sources can copper be extracted from?

A
  • copper rich ores
  • low grade ores
  • contaminated land
51
Q

What do we call LCAs that choose to ignore certain environmental impacts of a product?

A

Selective LCA

52
Q

Give an example of a factor that is not used to sort glass products for recycling?

A

Size

53
Q

Suggest why fluorine is added to drinking water

A
  • Improves dental health
  • Prevents tooth decay
54
Q

Why can’t we release our waste water directly into the environment?

A

Waste water can contain toxic chemicals, harmful microorganisms and other organic matter. All these things can cause pollutionand affect plants and animals, including humans.

55
Q

What % of the Earth’s water is freshwater?

A

3%

56
Q

What name is given to resources which may run out one day if not managed carefully?

A

Finite resources

57
Q

Examples of finite resources

A
  • Metals
  • Plastics
  • Coal
58
Q

What is a finite resource?

A

Finite resources are those that are being used up at a faster rate than they can be replaecd

59
Q

What is sustainable development?

A

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

60
Q

What is an alternative synthetic product to wool?

A

Acrylic fibre / polypropene

61
Q

What is an alternative synthetic product to silk?

A

nylon

62
Q

What is an alternative synthetic product to wood?

A

PVC, MDF

63
Q

What is an alternative synthetic product to cotton?

A

Polyester

64
Q

What is order of magnitude?

A

An order of magnitude is a division or multiplication by 10

65
Q

Why should estimations calculated be expressed as order of magnitudes?

A
  • There are uncertainties involved in the calculations
  • Predictions do not take into account recycling of resources
66
Q

What is potable water?

A

Water is not necessarily pure, but safe to drink

67
Q

What 3 sterlising agents are used to clean water?

A
  • UV light
  • Ozone (O3)
  • Chlorine