Chemistry in society


1) Explain the extraction of iron

The ore of iron is hematite (Fe O).the apparatus used for this purpose is called BLAST FUNACE. It is made up bricks to with stand the high temperature.
( DRAW THE FURNACE)
















Hot air is blown from the down part of the apparatus. This air contains oxygen. The other

raw materials used are coke(carbon) and lime stone .the apparatus is kept at high

temperature . The following reactions take place


1) Coke (carbon) reacts with oxygen to form carbon dioxide

C + O -------------------------- CO
2 2
2) This carbon dioxide react whit more coke to form carbon monoxide

CO+ C__________________________ CO
2

3) This carbon mono oxide reduces iron oxide to iron


CO+ Fe O _________________ Fe + CO
2 3 2

4) The lime stone decompose to calcium oxide and carbon dioxide

CaCO __________________________ CaO + CO
3 2

This calcium oxide is basic in nature. It reacts with acidic impurities to form

the neutral slag. Molten iron is collected at the bottom of the furnace. The slag is

collected at the top of the iron which can be tapped out



2) Explain the extraction of zinc by electrolysis



the ore of zinc is zinc sulphide. It is roasted in oxygen to form zinc oxide.


Zn S + O ______________________ Zn O + SO
2
Zinc oxide dissolved in sulfuric acid to form zinc sulphate( ZnSO ) Dissolving it

in water and electrolysis is carrying out.


AT CATHODE

Zn +2e______________ Zn (zinc is collected)

AT A NODE

4OH _________ 2 H O +O + 4e








3) Explain the extraction of zinc by reduction


The ore of zinc is zinc sulphide. It is roasted in oxygen to form zinc oxide.


Zn S + O ______________________ Zn O + SO


Zinc oxide is reduced to zinc with carbon monoxide in a blast furnace

ZnO+ CO _________________ Zn +CO




Explain the Purification of copper from impure copper block

Purification of copper is done by electrolysis. Impure copper

block is kept as anode and a pure thin copper wire is kept as cathode. Molten copper

sulphate is used as electrolyte

When electricity is passed through the electrolytic cell the copper ions

from impure block go to the place of copper ions in the copper sulhate solution.

Copper ions from the copper sulphate solution go to the cathode, take 2electrons and

get deposited as copper. As the time passes cathode will become bigger and anode

will become thinner and thinner. Impurity will be deposited don the cell.











Explain the extraction of metals in the reactivity series












Write down the uses of metals

Iron –
1. to make ship bodies,

2. to make alloys,

3. used as a catalyst in the manufacture of ammonia.

Copper-

house wiring

for electro plating

copper vessels


Aluminum-

aero plane body
kitchen vessels
food cans

Zinc-

1. Galvanising (for electro plating)