Chapter 9: Contact Process, Haber Process and Alloy
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Contact Process, Haber Process and Alloy
Transcript of Chapter 9: Contact Process, Haber Process and Alloy
- 1. Uses of sulphuric acid
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2. 1. Manufacture of detergents
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3. 2. Manufacture of fertiliser
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4. 3. Manufacture of artificalfibres
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5. 4. Manufacture of paint
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6. 5. Leather tanning
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7. 6. As electrolyte in car batteries
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8. 7. Remove oxides from the surface of metals (metallurgy )
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9. CONTACT Process
Manufacture of sulphuric acid
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10. The Manufacture of H2SO4, through the Contact Process
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11. Contact Process: Stage 1
In the furnace, molten sulphur is burnt in dry air to produce
sulphur dioxide, SO2. The gas produced is purified and
cooled.
S(l) + O2(g) SO2(g)
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12. Contact Process: Stage 2
In the converter, SO2 and excess oxygen gas, O2 are passed over a
few plates of vanadium (V) oxide, V2O5 catalyst at 450oC to produce
sulphur trioxide, SO3
2SO2(l) + O2(g) 2SO3(g)
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13. Contact Process: Stage 2
About 99.5% of the sulphur dioxide, SO2 is converted into sulphur
trioxide, SO3 through this reversible reaction.
2SO2(l) + O2(g) 2SO3(g)
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14. Contact Process: Stage 3
In the absorber, the sulphur trioxide, SO3 is first reacted with
concentrated sulphuric acid, H2SO4 to form a product called oleum,
H2S2O7.
SO3(g) + H2SO4(l) H2S2O7(l)
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15. Contact Process: Stage 3
The oleum, H2S2O7 is then diluted with water to produce
concentrated sulphuric acid, H2SO4 in large quantities.
H2S2O7(l)+ H2O(l) 2H2SO4(l)
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16. FAQ 1
The two reaction in the third stage are equivalent to adding
sulphur trioxide, SO3, directly to water
SO3 (g)+ H2O(l) H2SO4(l)
- Then why cant we just skipped concentrated sulphuric acid step [thus not forming oleum]?
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17. Answer
X
SO3 (g)+ H2O(l) H2SO4(l)
- This is not done in the industry, because sulphur trioxide, SO3 reacts too violently with water. This produces a lot of heat and a large cloud of sulphuric acid, H2SO4 mist.
18. The mist is corrosive, pollutes the air and is difficult to
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19. FAQ 2
Why dont we increase the pressure in the converter? So we can
produce more sulphur trioxide per day?
2SO2(l) + O2(g) 2SO3(g)
Answer: Yes, high pressure increases the rate of reaction, but it
cost very high also. So, the reaction is done at pressure close to
atmospheric pressure.
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20. Refresh again
Stage 1, in furnace
**O2 = burning
S(l) + O2(g) SO2(g)
Stage 2, in converter
**O2 = passed over catalyst
2SO2(l) + O2(g) 2SO3(g)
Catalyst: Vanadium (V) oxide
Temperature: 450oC
Stage 3, in absorber
SO3(g) + H2SO4(l) H2S2O7(l)
H2S2O7(l)+ H2O(l) 2H2SO4(l)
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21. Sulphur dioxide and environmental pollution
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22. Sulphur dioxide, SO2
Source:
By-products of the contact process
Burning of fossil fuels containing sulphur
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23. Sulphur dioxide, SO2
Causes acid rain (pH2.4-5.0)
Causes respiratory problems in humans
2SO2(g)+ O2(g) + 2H2O 2H2SO4(aq)
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24. Ammonia nh3 and its salt
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25. 1. Manufacture of fertilisers
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26. 2. Manufacture of synthetic fibers
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27. 3. Manufacture of explosives
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28. Haber process
Manufacture of Ammonia
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29. The Manufacture of Ammonia, NH3 through the Haber Process
Ratio 1:3
N2(g) + 3H2(g) 2NH3(g)
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30. ALLOYS
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31. Metals are Ductile/Can be stretched ()
The orderly arrangement of atoms in metals enables the layers of
atoms to slide on another when force is applied
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32. Metals are Malleable
There are some inperfections in the orderly arrangement of atoms in
metals that allow some empty space in between the atoms. When a
metal is knocked, atoms slide.
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33. Alloy
Definition: A mixture of two or more elements with a certain fixed
composition in which the major component is a metal.
Properties of pure metals can be improved => stronger, harder,
resistant to sorrosion, have a better furnish and lustre.
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34. GOLD (24K, 18K)
Pure gold 24K (24-carat)
18K Gold has 18 parts of gold and 6 parts of other metals
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35. Bronze (Copper + Tin)
Statues, monuments
Medals, swords, artistic materials
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36. Brass (Copper + Zinc)
Musical instrument
Kitchenware
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37. Steel (Iron + Carbon)
Buildings and bridges
Body of cars & railway tracks
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38. Stainless steel (Iron + Carbon + Chromium)
Cutlery
Surgical Instruments
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39. Duralumin (Aluminium, Copper, Magnesium, Mangenese)
Body of aeroplanes & bullet trains
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40. Pewter (Tin, Copper, Antimony)
souvenirs
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41. The Formation of Alloy
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