industrial processes

Question 1

what is another name for aluminium oxide and what is its formula ?

Answer 1

bauxite and al203

Question 2

what do we add to aluminium oxide to lower the melting point

Answer 2

cryolite

Question 3

what temperature does the electrolysis of aluminium oxide take place ?

Answer 3

850-950 degrees

Question 4

in the electrolysis of aluminium oxide what goes to the anode and what goes to the cathode

Answer 4

aluminium - cathode

oxygen -anode

Question 5

what are the anodes made out of in the electrolysis of aluminium

Answer 5

graphite

Question 6

why must the anodes be regularly replaced in the electrolysis of aluminium

Answer 6

because the oxygen being released reacts with the graphite to for carbon dioxide

Question 7

what are the characteristics and uses

of aluminium

Answer 7

• light weight , resistant to corrosion due to oxide layer, strong when alloyed
• drinks can , foil , electricity cables

Question 8

how do you extract aluminium from aluminium oxide

Answer 8

electrolysis

Question 9

what is the use of a blast furnace

Answer 9

to extract iron from iron ore ( iron oxide / haematite)

Question 10

what raw materials are used in a blast furnace ?

Answer 10

• coke (carbon )
• iron ore ( iron oxide )
• limestone
• hot air

Question 11

step by step of the reactions in the blast furnace

Answer 11

1) oxygen reacts with the carbon to form co2
2) the hot co2 reacts with more carbon to form carbon monoxide which is a reducing agent
3)the co reacts with the haematite leaving the products , iron and carbon dioxide
4) the limestone ( caco3 ) decomposes to form caco and carbon dioxide
the caco reacts with silicon dioxide to form slag

Question 12

why is the reaction of carbon and oxygen to form carbon dioxide so important in the blast furnace ?

Answer 12

its exothermic and gives energy to the reaction

Question 13

what temperature is the hot air blasted in the blast furnace

Answer 13

1800 degrees

Question 14

what kind of iron comes out

of the blast furnace ?

Answer 14

pig iron - it has carbon impurities

Question 15

what does the haber process produce ?

Answer 15

Ammonia

Question 16

whats the chemical formula of

ammonia

Answer 16

nh3

Question 17

what temperature is needed for the haber process and why

Answer 17

450 degrees which is quite low for an industrial process , its low enough that the equilibria is shifted to a high ammonia yield but not too low to give a slow rate of reaction

Question 18

what pressure is required for the haber process and why ?

Answer 18

200 atm , high pressure as there are less molecules on the right hand side than left hand side meaning the reaction shifts to a higher yield of
ammonia

Question 19

what catalyst is required for the haber process

Answer 19

an iron catalyst

Question 20

what is the equilibria reaction in the haber process and what kind of reaction is this

Answer 20

n2 + 3h2 2NH3

its exo thermic

Question 21

what are the uses of ammonia ?

Answer 21

fertilisers
nitric acid
making nylon

Question 22

what does the contact process produce ?

Answer 22

sulphuric acid

Question 23

what are the raw materials in the contacts process v

Answer 23

sulphur and air

Question 24

what are the steps of the contact process and which reaction is the equilibrium reaction

Answer 24

1)make sulphur dioxide
•burn sulphur in air
•heat sulphide ore in air
1)make sulphur trioxide -equilibria
•2so2 + o2  2so3 
•its an exothermic reaction 
•conditions:
   -vanadium catalyst
   -2 atm high pressure
   -450temp
   -excess oxygen
3)make it acidic
•dissolve sulphur trioxide in a little bit of sulphuric acid 
•then add water

Question 25

in the contact process why dont we just add water to sulphur trioxide

Answer 25

because it forms sulphuric acid steam and is very dangerous

Question 26

in the contact process what is the name

of the product when we dissolve so3 in suphuric acid

Answer 26

oleum or fuming sulphuric acid

Question 27

what is sulphuric acid used for ?

Answer 27

• making fertilisers
• making detergents
• making paint