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Chemistry - C1 > C1.3 Metals and their uses > Flashcards

C1.3 Metals and their uses Flashcards

1
Q

What does it mean if an ore is concentrated?

A

getting rid of the unwanted rocky material

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2
Q

Why is gold not found as a compound?

A

As it is very unreactive

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3
Q

What are the 2 ways a metal can be extracted from their ores chemically

A

electrolysis

reduction

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4
Q

When can metals be extracted by their oxides with reduction?

A

When the metal is less reactive than carbon.

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5
Q

What happens during reduction with carbon?

A

oxygen is removed from the compound

eg iron oxide is reduced in the furnace to make iron

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6
Q

How are metals that are more reactive than carbon extracted?

A

By electrolysis of molten compounds.

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7
Q

Why is electrolysis more expensive than reduction with carbon?

A

it uses a lot of energy.

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8
Q

Describe the extraction of copper from copper rich ores

A

Copper is first extracted from its ores in a furnace- reduction with carbon. The copper is then purified by electrolysis so it conducts electricity better- electrical wiring

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9
Q

What 2 ways can copper be extracted from low grade ores?

A

phytomining

bioleaching

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10
Q

Describe phytomining

A

a way of extracting copper from a low grade ore

uses plants to absorb metal compounds. Plants are then burned to produce ash that contains the metal compounds.

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11
Q

Describe bioleaching

A

A way to extract copper from low grade ores

uses bacteria to produce leachate solutions that contain metal compounds

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12
Q

What is a metal ore?

A

A rock which contains enough metal to make it economic to extract the metal.

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13
Q

Describe how copper can be obtained from solutions of copper salts

A

by electrolysis

Copper is attracted to the negative electrode as it is a positively charged ion. Here, it gains electrons.

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14
Q

Describe how ion can be used to obtain copper from copper sulfate

A

Scrap ion can be used to displace copper from solution as iron is more reactive than copper

copper sulfate + iron — iron sulfate + copper

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15
Q

Why can aluminium and titanium not be extracted from their oxides by reduction with carbon?

A

As they are more reactive than carbon

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16
Q

Why are methods to extract aluminium and titanium expensive?

A
  • There are many stages in the process

- Large amounts of energy are needed.

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17
Q

Why is metal extraction bad for the environment?

A
  • noise
  • scarring of the landscape
  • loss of habitats
  • deep mine shafts can be dangerous if abandoned
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18
Q

What are some benefits of metal extraction?

A
  • useful products can be made
  • provides local people with jobs
  • brings money into the area- so services such as transport and health are improved.
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19
Q

Why is recycling metals important?

A
  • conserves resources- finite amount of each metal on Earth
  • reduces landfill
  • mining and extracting metals takes a lot of energy- so less fossil fuels are used if you recycle.
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20
Q

Iron straight from the blast furnace contains what percentage of iron?

A

96%

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21
Q

What do the impurities of iron straight from the blast furnace make it like?

A

brittle - so it has limited uses

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22
Q

What is iron straight from the blast furnace used for and why?

A

cast iron because of its strength in compression

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23
Q

What is steel a mixture of?

A

iron and carbon

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24
Q

what is a property of low-carbon steel?

A

easily shaped

25
Q

what is a property of high-carbon steels?

A

hard

26
Q

what is a property of stainless steel?

A

resistant to corrosion

27
Q

Why are pure gold, copper, iron and aluminium mixed with small amounts of similar metals?

A

They are too soft for many uses and so are mixed with small amounts of similar metals to MAKE THEM HARDER for everyday use.

28
Q

Why are alloys harder than pure metals?

A

Different elements have different sized atoms. This distorts the regular layers, making it difficult for them to slide over each other.

29
Q

What are the elements in the central block of the periodic table know as ?

A

transition metals

30
Q

Describe the properties of transition metals

A
  • good conductors of heat and electricity

- bent or hammered into shape

31
Q

What are some properties of copper that make it useful for electrical wiring and plumbing?

A
  • good conductor of electricity and heat
  • can be bent but is hard enough to be used to make pipes or tanks
  • does not react with water
32
Q

Why are aluminium and titanium useful metals?

A

low density

resistance to corrosion

33
Q

What are some disadvantages of using metals as structural materials?

A
  • Some corrode when exposed to air and water so need to be painted —– if a metal corrodes, it loses its strength and hardness
  • Metal fatigue- leads to metals breaking- dangerous
34
Q

Why is titanium more expensive than iron?

A

there are more stages in the process

more energy/materials are needed to extract it

titanium is more reactive than titanium so cannot be extracted using carbon

35
Q

Why is air removed and replaced with argon in the reaction between titanium chloride and magnesium metal to produce titanium?

A

because oxygen in the air would react with magnesium and produce magnesium oxide

whereas argon is unreactive so does not react

36
Q

Why is copper extracted from ores containing a low percentage of coper compounds?

A

copper ores are running out and are harder to find

copper metal is in demand

now economical to extract copper from low grade ores

37
Q

Why is it difficult to dispose waste rock?

A

takes up a lot of space

38
Q

What is used in phytomining to remove copper compounds from the land?

A

plants

39
Q

what are some advantages and disadvantages of recycling materials from a ball point pen?

A

conserves resources

reduces use of landfill

less use of energy

less carbon dioxide produced

made from different materials

diffuculty and cost of separating the different materials

40
Q

Why are alloys used in a ball point pen?

A

so it is hard and strong

so it is resistant to corrosion so it does not rust

41
Q

Why does extracting copper from the land using traditional methods have a major environmental impact?

A
  • produces large amounts of solid waste
  • causes atmospheric pollution from carbon dioxide + sulphur dioxide
  • more lorries to transport bulky material
42
Q

Why is it economical to use scrap iron to get copper?

A

iron is cheap

43
Q

Why can iron be used to get copper from copper sulfate solution?

A

iron displaces copper from solutions of its salts

because iron is more reactive than copper

44
Q

What are some advantages of phytomining rather than using traditional methods to extract metal?

A
  • carbon neutral - as plants remove carbon dioxide from the atmosphere as they grow
  • less expensive as less energy is needed to extract the small amounts of copper
45
Q

Suggest a disadvantage of phytomining rather than traditional methods to extract metals

A

it is not a continuous process as it takes a long time for plants to grow

46
Q

What is smelting?

A

When copper is extracted from copper rich ores by heating the ores in a furnace

47
Q

Suggest why an ore needs to be separated before the metal is extracted

A

as the ore is not pure

so the other compounds need to be removed

48
Q

Describe how cast iron is converted into steel

A

in the furnace, oxygen reacts with the carbon in the iron

which reduces the percentage of carbon in the mixture

as carbon dioxide is produced

49
Q

what is the property of aluminium which makes it more suitable for overhead cables than copper?

A

aluminium is low density

50
Q

How can you tell that copper is a transition metal and aluminium is not a transition metal for their position in the periodic table?

A

copper is in the central block in the periodic table

whereas aluminium is in group 3

51
Q

What is an alloy?

A

a mixture of metals

52
Q

explain why the need for copper will cause a problem in the future

A

as we are running out of copper ores

53
Q

suggest ways society could overcome the problem that copper ores are running out

A

use low grade copper ores- from phytomining/bioleaching

reuse/recycle copper

use other materials instead

54
Q

what is meant by a smart alloy?

A

an alloy that can return to its original shape when heated

55
Q

Name the element that is removed from ores when they are reduced

A

oxygen

56
Q

how is iron ore reduced in a blast furnace to make iron?

A

the iron ore is heated

carbon in the air reacts with oxygen in the ore - displaces the oxygen

57
Q

Explain why copper from areas that contain a very low percentage of copper compound is not extracted by smelting

A

land contains very little copper

uneconomical

58
Q

What happens to copper ions during electrolysis?

A

copper ions are attracted to the negative electrode

where they are reduced (gain 2 electrons)

copper metal is formed

Chemistry - C1 (7 decks)

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