Extraction And Uses Of Metals

Question 1

Infinite or finite number of metal ores?

Answer 1

They are know as “finite resources”

Question 2

How does the reactivity series help us with extracting metals?

Answer 2

The more reactive a metal is, harder it is to extract it from a compound

Question 3

What is the reaction called that separates pure metal from their oxides?

Answer 3

The reaction the separates a metal from the oxygen in its oxide is called a reduction reaction

Question 4

What is reduction? Example

Answer 4

Loss of oxygen

E.G. Copper oxide + carbon —> copper + oxygen

Question 5

What is the substance that is oxidised called in a reduction reaction?

Answer 5

The reducing agent as is reduced to its ‘normal’ form

Question 6

How is a reduction reaction done with carbon?

Answer 6

A less reactive metal ore is heated with carbon monoxide

Question 7

What makes a metal compound a metal ore?

Answer 7

If it has enough metal in it that it is pronounced worth extracting

Question 8

How do you extract aluminium?

Answer 8

By using electrolysis

Question 9

What is the symbol for pure aluminium oxide?

Answer 9

Al O

2 3

Question 10

What is aluminium a main ore?

Answer 10

Bauxite

Question 11

Why don’t we melt bauxite?

Answer 11

It has a very high boiling point at over 2000°C as it would be very expensive

Question 12

What is aluminium oxide dissolved in to bring the boiling point down?

Answer 12

Cryolite ( a less common ore of aluminium ) this brings the boiling point down to around 900°C which makes it easier to melt

Question 13

Why is electrolysis expensive?

Answer 13

• Requires a lot of electricity and energy to heat the mixture = expensive
• The disappearing positive electrode needs frequent replacement

Question 14

What is the equation for the decomposition of of aluminium oxide?

Answer 14

Aluminium oxide —> aluminium + oxygen

Question 15

What is the negative electrode known as?

Answer 15

Cathode

Question 16

What is the positive electrode known as?

Answer 16

Anode

Question 17

Why does the molten aluminium conduct electricity?

Answer 17

Because it contains free ions which can transport electricity

Question 18

What happens to the positive aluminium ions?

Answer 18

They are attracted to the negative electrode called the cathode where they pick up electrons and turn into aluminium atoms then they sink to the bottom

Question 19

What happens to the negative oxygen ions during electrolysis?

Answer 19

They are attracted to the positive electrode called the anode where they lose electrons. The oxygen atoms react together to form O2 or with the carbon anode as well to form to CO2

Question 20

Why does the anode or the positive electrode often need replacing?

Answer 20

Because it is constantly reacting with oxygen and so gets worn down

Question 21

What is the symbol equation for what is happening at the cathode?

Answer 21

Al 3+ + 3e - —> Al

Question 22

What is the symbol equation for what is happening at the anode?

Answer 22

2O 2- —> O + 4e -

2

Question 23

Where is iron extracted from? What is its symbol?

Answer 23

Iron is extracted from its ore called haematite
Fe O
2 3

Question 24

How is iron extracted from its ore?

Answer 24

By reduction (removal of oxygen) in a blast furnace

Question 25

What are the ingredients that are put into a blast furnace and what do they do?

Answer 25

Iron ore - contains iron Coke (almost pure carbon) - reducing the iron oxide to iron metal Limestone - takes away impurities in the form of slag

Question 26

What is the first step in extracting iron from and iron ore using a blast furnace?

Answer 26

Hot air is blasted into the furnace, making the Coke burn much faster than normal, raising the temperature inside the furnace to about 1500°C

Question 27

What is the second step in extracting iron from and iron ore using a blast furnace? What is the symbol equation?

Answer 27

Coke burns and produces carbon dioxide Carbon + oxygen ---> carbon dioxide C + O ---> CO 2 2

Question 28

What is the third step in extracting iron from and iron ore using a blast furnace? What is the symbol equation?

Answer 28

The carbon dioxide reacts with the u burnt coke to form carbon monoxide. Carbon dioxide + carbon ---> carbon monoxide CO + C ---> 2CO 2

Question 29

What is the forth step in extracting iron from and iron ore using a blast furnace? What is the symbol equation?

Answer 29

The carbon monoxide then reduces the iron ore to iron Carbon monoxide + iron (III) oxide ---> carbon dioxide + iron 3CO + Fe O ---> 3CO + 2Fe 2 3 2

Question 30

What is the final step in extracting iron from and iron ore using a blast furnace?

Answer 30

The iron is molten at this temperature and also is very dense. As such it falls straight to the bottom of the furnace and is tapped off there

Question 31

What is the main impurity and what removes it?

Answer 31

Sand (silicon dioxide) is the main impurity and it is removed by limestone

Question 32

How does the limestone remove the sand?

Answer 32

The limestone is decomposed by the heat into calcium oxide and CO(2) CaCO ---> CaO + CO 3 2 The calcium oxide reacts with the sand to form calcium silicate or slag which is molten can be tapped off CaO + SiO ---> CaSiO 2 3

Question 33

What can the slag be used for?

Answer 33

The cooled slag is solid and can be used for roadbuilding or for fertiliser

Question 34

What properties do iron and aluminium share?

Answer 34

- Both metals - Both dense and shiny - Both have high melting points - Both have high tensile strength (strong and hard to break) - Both malleable (hammered into shape) - Both good conductors of heat energy and electricity

Question 35

What is wrought iron, and what is it used for?

Answer 35

It is completely pure iron that is malleable and often used for ornamental gates and railings

Question 36

What are two examples of iron alloys?

Answer 36

Cast iron | Steel

Question 37

What is cast iron and what is it used for?

Answer 37

It is iron with a mixture of carbon and silicon. It is very hard but brittle. It is often used for manhole covers and some cooking pans

Question 38

What is steel and what is it used for?

Answer 38

Steel is an alloy made up of iron, carbon and usually some other metals. It is harder than pure iron but can be hammered and made easily into sheets and welded together. These properties mean steel is great making carbodies and girders (for construction)

Question 39

Why is cutlery made out of stainless steel?

Answer 39

Because pure iron rusts very easily. Stainless steel is an alloy made from iron and chromium and it does not rust.

Question 40

What is the main way that aluminium different from iron?

Answer 40

Aluminium does not corrode easily

Question 41

Why is it useful that aluminium does not corrode?

Answer 41

Because it means that it can be used for products where liquid is involved and will not rust such as with fizzy drink cans

Question 42

Why is aluminium particularly useful for aeroplanes and bicycle frames?

Answer 42

Because aluminium is a lot less dense than iron meaning that it is quite light. It is used for aeroplanes because of this

Question 43

Talk about aluminium and aluminium oxide. How is it useful?

Answer 43

Aluminium react very quickly with oxygen in the air to form aluminium oxide. A nice protective layer of aluminium oxide sticks firmly to the aluminium below and stops any further reaction taking place.