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The extraction of aluminium from its ore takes place in two stages, purification stage and electrolysis stage. The diagram below shows the set up for the...

The extraction of aluminium from its ore takes place in two stages, purification stage
and electrolysis stage. The diagram below shows the set up for the electrolysis stage.

(a) Name the ore from which aluminium is extracted.
(b) Name one impurity which is removed at purification stage.
(c) Label on the diagram each of the following:
Anode
Cathode
Region containing the electrolyte
(d) The melting point of aluminium oxide is 2054⁰C but electrolysis is done between 800⁰C -
900⁰C.
(i) Why is the electrolysis not carried out at 2054⁰C.?
(ii) What is done to lower the temperature of the electrolysis cell to 800⁰C - 900⁰C?
(iii) The aluminium which is produced is tapped off as liquid. What does this imply
about its melting point?
(e) A typical electrolysis cell uses a current of 40000 ampheres. Calculate the mass (in kilograms) of aluminium produced in one hour.

Answers

a) Bauxite.
b) Iron(iii)oxide/silicon(iv)oxide/dioxide/silica

d)(i) it is uneconomical/expensive because a lot of energy is required to produce this high
temperature.
(ii) Addition of cryolite
(iii) The melting point is below 800⁰C.

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sharon kalunda answered the question on May 20, 2019 at 06:22

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