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AS Chemistry - Unit 2 > Unit 3.2.7 - Extraction of Metals > Flashcards

Unit 3.2.7 - Extraction of Metals Flashcards

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1
Q

What is an ore?

A

A natural substance that it is economically worthwhile to extract metal from

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2
Q

What are the two most common types of ore?

A

Oxides and sulphides

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3
Q

What’s the first step in extracting a metal from a sulphide ore?

A

Turn it into an oxide by roasting it in air

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4
Q

What does roasting a metal sulphide in air produce?

A

A metal oxide and sulphur dioxide

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5
Q

What is the equation for when zinc sulphide is roasted in air?

A

2ZnS + 3O2 ————-> 2ZnO +2SO2

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6
Q

What is bad about converting sulphide ores into metal oxides?

A

The process produces sulphur dioxide which forms acidic rain and damages trees, fish and limestone buildings

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7
Q

What is the sulphur dioxide converted to after roasting sulphide ore in air so that it can’t cause acid rain?

A

Sulphuric acid

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8
Q

What are used as reducing agents to extract metals less reactive than carbon from a metal oxide?

A

Carbon and carbon monoxide

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9
Q

How is iron extracted from iron oxide?

A

By reducing it with carbon or carbon monoxide in a blast furnace

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10
Q

What temperature is the blast furnace when you are extracting iron from its ore?

A

More than 700C

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11
Q

What is the equation for when iron oxide is reduced by carbon?

A

2Fe2O3 + 3C ————-> 4Fe + 3CO2

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12
Q

What is the equation for when iron oxide is reduced by carbon?

A

Fe2O3 + 3CO ————-> 2Fe + 3CO2

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13
Q

What is the formula for the ore of iron?

A

Fe2O3

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14
Q

How is manganese extracted from manganese oxide?

A

By reducing it with carbon or carbon monoxide in a blast furnace

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15
Q

What temperature is the blast furnace when you are extracting manganese from its ore?

A

Around 1200C

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16
Q

Doe extracting iron or manganese from their ore require a higher temperature?

A

Manganese

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17
Q

What is the equation for when manganese oxide is reduced by carbon?

A

MnO2 +C ————-> Mn + CO2

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18
Q

What is the equation for when manganese oxide is reduced by carbon monoxide?

A

MnO2 +2CO ————-> Mn + 2CO2

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19
Q

What is the formula for an ore of manganese?

A

MnO2

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20
Q

What is a copper ore of copper?

A

Malachite

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21
Q

What is the formula for malachite?

A

CuCO3

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22
Q

What the two methods for extracting copper from copper carbonate?

A
  1. ) Directly heat with carbon

2. ) Heat the copper carbonate until it decomposes into copper oxide and then reduce the oxide with carbon

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23
Q

What is the equation for when copper is extracted from copper carbonate by directly heating it with carbon?

A

2CuCO3 + C ————-> 2Cu + 3CO2

24
Q

What are the two equations for extracting copper from copper carbonate by heating it until it decomposes and then reducing it?

A

CuCO3 ————-> CuO + CO2

2CuO + C ————-> 2Cu + CO2

25
Q

What three metals cant be extracted from their ores of metal oxide by reduction with carbon?

A

Titanium, Tungsten and Aluminium

26
Q

Why don’t you extract tungsten from its ore of tungsten oxide by reduction with carbon?

A

It leaves impurities which makes the metal brittle

27
Q

Why can’t you extract aluminium for its ore of aluminium oxide by reduction with carbon?

A

It is more reactive than carbon, it also would require a very high temperature to reduce it not making extraction worthwhile through this process

28
Q

Why don’t you extract titanium from its ore of titanium oxide by reduction with carbon?

A

You get titanium carbonate which ruins the metal

29
Q

What is the equation for what happens when you try to reduce titanium oxide with carbon?

A

TiO2 + 3C ————-> TiC + 2CO2

30
Q

What process is used to extract aluminium from its ores of aluminium oxide?

A

Electrolysis

31
Q

What is the name for the most common ore of aluminium?

A

Bauxite

32
Q

What happens to the bauxite before it goes through electrolysis?

A

It is purified

33
Q

What is mixed with aluminium oxide before electrolysis and why?

A

Molten cryolite to reduce its melting point to about 900C

34
Q

What happens to the aluminium oxide during electrolysis?

A

The aluminium ions gain electrons and are reduced at the cathode forming aluminium atoms
The oxide ions lose electrons and are oxidised at the anode forming oxygen molecules

35
Q

What is the equation for the reaction that happens at the cathode during the electrolysis of aluminium oxide?

A

Al3+ + 3e- ————-> Al

36
Q

What is the equation for the reaction that happens at the anode during the electrolysis of aluminium oxide?

A

2O2- ————-> O2 + 4e-

37
Q

What happens to the aluminium when it is formed during the electrolysis of aluminium oxide?

A

It is molten and sinks to the bottom of the cell where it can be tapped off

38
Q

What type of process is extracting titanium from its ore of titanium oxide?

A

A batch process with several different stages

39
Q

What is the first step in extracting titanium from its ore of titanium oxide?

A

It is converted to titanium chloride by heating it to about 900C with carbon in a stream of chlorine gas

40
Q

What is the equation for when titanium oxide is converted to titanium chloride ?

A

TiO2 + 2Cl2 + 2C ————-> TiCl4 +2CO

41
Q

What happens to the titanium chloride when it is first produced during the extraction of titanium and how?

A

It is then purified by fractional distillation under an inert atmosphere of argon gas

42
Q

What is the second step in extracting titanium from its ore of titanium oxide?

A

Heated in a furnace at about 1000C with a more reactive metal like sodium in an inert atmosphere of argon gas

43
Q

What is the equation for when titanium chloride is converted to titanium?

A

TiCl4 + 4Na ————-> Ti + 4NaCl

44
Q

Why is an inert atmosphere of argon used in the second step of the extraction of titanium from its ore of titanium oxide?

A

To prevent the titanium chloride and sodium from reacting with oxygen or water vapour in the air

45
Q

How is tungsten extracted from its ore of tungsten oxide?

A

Reducing it with hydrogen in a furnace with temperatures above 700C

46
Q

What is the equation for when titanium is extracted from its ore of titanium oxide?

A

WO3 + 3H2 ————-> W + 3H2O

47
Q

Why is it worth using hydrogen as a reducing agent during the extraction of titanium even though it is more expensive?

A

You get purer tungsten

48
Q

What is one disadvantage of using hydrogen as a reducing agent when extracting tungsten other than its cost?

A

Safety risks as it is highly explosive in air

49
Q

What are four advantages of recycling metals?

A
  1. ) Saves raw materials as ores are a finite resource
  2. ) Saves energy as recycling metals takes less energy than extracting metals
  3. ) Reducing waste sent to landfills
  4. ) Mining for new metals damages the landscape
50
Q

What are three disadvantages of recycling metals?

A
  1. ) Collecting and sorting metals from other waste can be difficult and expensive
  2. ) Recycled metals often impurities
  3. ) Recycling metals might not produce a consistent supply to meet demand
51
Q

What is one use for recycled scrap iron?

A

Extracting copper from aqueous solution

52
Q

What are the four steps in how recycled scrap iron is used to extract copper?

A
  1. ) Copper ore is added to acidified water
  2. ) Solution collected and scrap iron is then added
  3. ) Iron dissolves and reduces the copper ions
  4. ) The copper then precipitates out of the solution and is removed
53
Q

Why is the copper ore added to acidified water before extracting the copper using scrap iron?

A

So that the copper compounds can dissolve and the copper ions are in the solution

54
Q

What is the equation for how iron reduced copper ions in aqueous solution?

A

Cu2+ + Fe ————-> Cu + Fe2+

55
Q

What type of ore is copper extracted by reduction using scrap iron?

A

Low grade ores

56
Q

Why is scrap iron used to extract copper only from low grade ores?

A

It produces copper more slowly and has a lower yield

57
Q

What are three advantages of using scrap iron to extract copper rather than reduction with carbon?

A
  1. ) Scrap iron cheaper than carbon
  2. ) You don’t need as high temperatures saving energy and money
  3. ) No carbon dioxide produced

AS Chemistry - Unit 2 (11 decks)

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