Chemistry In Industry (Metals, Iron, Aluminium)

Question 1

Most metals are found in _______

Answer 1

Ores

Question 2

Metals often have to be separated from their ________

Answer 2

Oxides

Question 3

Metals above carbon in the reactivity series are extracted by what method

Answer 3

Electrolysis

Question 4

Metals below carbon in the reactivity series are extracted by what method

Answer 4

Heating with carbon monoxide

Question 5

What is used in the electrolysis of aluminium

Answer 5

Molten cryolite

Question 6

Why is molten cryolite used in the electrolysis of aluminium

Answer 6

The aluminium oxide dissolves in it and brings the temperature down to about 900C

Question 7

Aluminium is extracted from aluminium oxide. Why does molten aluminium oxide conduct electricity

Answer 7

Because it has free ions

Question 8

Electrolysis of aluminium oxide:
Positive Al3+ ions are attracted to the negative electrode (________)
The negative O2- ions are attracted to the positive electrode (________)

Answer 8

Cathode

Anode

Question 9

Why does the positive anode often need repacing

Answer 9

By getting worn down by the oxygen

Question 10

Half equation of aluminium oxide a the cathode:

Answer 10

Al3+ + 3e- –> Al

Question 11

Half equation of aluminium oxide at the anode:

Answer 11

2O2- –> O2 + 4e-

Question 12

Complete equation for the decomposition of aluminium oxide

Answer 12

Aluminium oxide –> Aluminium + Oxygen

Question 13

Why is electrolysis expensive

Answer 13

Lots of electricity used

Replacement of positive electrodes (anode) needed

Question 14

What are the raw materials in the extraction of iron

Answer 14

Iron ore
Coke
Limestone

Question 15

What is coke and what does it do

Answer 15

Almost pure carbon (reduces the iron oxide to iron metal)

Question 16

What does limestone do

Answer 16

Limestone takes away impurities in the form of slag

Question 17

What is the first step in the reduction of iron ore to iron

Answer 17

Hot air is blasted in, making the coke burn faster than usual. This raises the temperature to about 1500C

Question 18

The coke burns and produces Carbon dioxide.

What is the equation for this

Answer 18

C + O2 –> CO2

Carbon + Oxygen –> Carbon dioxide

Question 19

The Co2 then reacts with the unburnt coke form CO.

What is the equation for this

Answer 19

CO2 + C –> 2CO

Carbon dioxide + Carbon –> Carbon monoxide

Question 20

The carbon monoxide then reduces the iron ore to iron.

What is the equation for this

Answer 20

3CO + Fe2O3 –> 3CO2 + 2Fe

Carbon monoxide + Iron (|||) oxide –> Carbon dioxide + Iron

Question 21

What is the main impurity in the blast furnace

Answer 21

Sand (Silicon dioxide)

Question 22

What removes the silicon dioxide

Answer 22

Limestone

Question 23

The limestone is decomposed by the heat into calcium oxide and CO2.
What is the equation for this

Answer 23

CaCO3 –> CaO + CO2

Question 24

The calcium oxide then reacts with the sand to form calcium silicate (slag), which is molten and can be tapped off.
What is the equation for this

Answer 24

CaO + SiO2 —> CaSio3 (molten slag)

Question 25

What can cooled slag be used for?

Answer 25

Road building | Fertiliser

Question 26

Describe how iron is produced from iron ore coke in the blast furnace

Answer 26

The coke burns (with oxygen) to produces CO2 The Co2 reacts with the unburnt coke to form CO The CO reduces the iron ore to iron (+ CO2)

Question 27

Properties of both iron and aluminium:

Answer 27

``` They both: Are dense Are good conductors of heat and electricity Are malleable Are strong Have high melting points ```

Question 28

What is wrought iron and what are its uses

Answer 28

Pure iron | Gates, railing

Question 29

You can mix iron with other elements to make _______

Answer 29

Alloys

Question 30

Stainless steel is an alloy of iron. What can it be used for

Answer 30

Cutlery, cooking pans

Question 31

What is the main problem with iron

Answer 31

It rusts

Question 32

What is aluminium used for

Answer 32

Aeroplanes | Drink Cans

Question 33

What makes aluminium more suited for aeroplanes than iron

Answer 33

It doesn't corrode | It is lighter (less dense)