Chemistry Reference
In-Depth Information
(iii)
Why is the reaction between calcium oxide
and silicon(
iv
) oxide called an acid-base
reaction?
(iv)
Describe what happens to the liquid iron
and slag when they reach the bottom of the
furnace.
e
Why do you think that the furnace used in the
extraction of iron is called a blast furnace?
5
The iron obtained from the blast furnace is known
as pig or cast iron. Because of the presence of
impurities, such as carbon, it has a hard and brittle
nature. Most of this type of iron is therefore
converted into steel in the basic oxygen process.
During this process either all or some of the carbon
is removed. Calculated quantities of other elements
are then added to produce the required type of steel.
a
Explain the meaning of the term alloy as applied
to steel.
b
Name two impurities, other than carbon, which
are present in cast iron and which are removed
completely during the steel manufacture.
c
Describe the method of steel manufacture used
which removes the impurities referred to in
b
.
d
Name two metallic elements which may be
added to the basic oxygen furnace to produce
different varieties of steel.
e
Give two uses of stainless steel.
f
Give two advantages of stainless steel compared
with cast iron.
6
The metal titanium is extracted from its ore rutile
(TiO
2
).
a
Describe the processes involved in the extraction
of titanium from rutile.
b
Name the area of the Periodic Table in which
titanium is found.
c
The final part of the process involves the
following reaction:
TiCl
4
(
l
) + 4Na(
l
) → 4NaCl(
s
) + Ti(
s
)
(i)
Calculate the quantity of titanium produced
from 19 tonnes of titanium(
iv
) chloride
(TiCl
4
).
(ii)
How much sodium would have to be used
to extract the titanium from the 19 tonnes
of TiCl
4
used in (
i
)?
d
Give two uses of titanium metal.
7
Zinc can be reacted with steam using the apparatus
shown. When gas
A
is collected, mixed with air
and ignited it gives a small pop. A white solid
B
remains in the test tube when the reaction has
stopped and the apparatus cooled down.
rocksil wool
soaked in
water
A
B
heat
heat
water
a
Name and give the formula of gas
A
.
b (i)
Name the product formed when gas
A
burns in air.
(ii)
Write a balanced chemical equation for this
reaction.
c (i)
Name white solid
B
.
(ii)
Write a balanced chemical equation to
represent the reaction between magnesium
and steam.
d
Name two other metals which could be safely
used to replace zinc and produce another sample
of gas
A
.
e
When zinc reacts with dilute hydrochloric
acid, gas
A
is produced again. Write a balanced
chemical equation to represent this reaction and
name the other product of this reaction.
8
Copper is extracted in the final stage by roasting
copper(
i
) sulfide (Cu
2
S) in a current of air. This
converts the sulfide to the metal.
Cu
2
S(
s
) + O
2
(
g
) → 2Cu(
s
) + SO
2
(
g
)
a (i)
What is the name of the chemical process
by which copper(i)
i
) sulfide is converted to
copper?
(ii)
At what temperature does this process take
place?
b
It is a very expensive business to maintain the
high temperature needed to efficiently convert
copper(
i
) sulfide to copper. How are the heating
costs offset?
c
Calculate the quantity of copper(i)
i
) sulfide
required to produce 1270 tonnes of copper.
(
A
r
: O = 16; S = 32, Cu = 63.5)
d
For use in electrical wiring, the copper must
be 99.99% pure. How is the copper purified to
obtain this high purity?
