Page 65 - Science Class 08

Coke is first heated above 1000 °C by forcing air
through it. Then air apply is cut off and steam is
allowed to pass through the hot coke. This
process is called steam run. This process is
again and again repeated un l the en re coke
is used up. Water gas is produced during the
steam run.
Coal gas : On destruc ve dis lla on of
bituminous coal, coal gas is produced. The
destruc ve dis lla on is carried out in ver cal
retorts made up of fine clay or silica bricks. The
required temperature for this chemical change
is between 1000-1200°C.
Producer Gas : When air is passed over red hot
coke, producer gas is produced in contents of
carbon monoxide and nitrogen.
2C + O + 4N Õ 2CO + 8N
2
2
2
coke air producer gas
Producer gas is not highly combus ble because
it has a high nitrogen content which is non-
combus ble material.
1. What is coal?
2. How does coal get formed under the
earth?
3. Why Anthracite is considered as the best
type of coal?
4. Why coal is the most widely used fossil
fuel?
5. What is destruc ve dis lla on?
6. How coke is obtained?
7. Write the uses of coal tar.
8. What do you mean by the process of
steam gas?
Science-8
NATURAL GAS
Like coal and petroleum, natural gas is also an
important fuel. It is also found deep inside the
earth’s crust. Its extrac on is similar to the
extrac on of petroleum. It is also extracted
through pipes. It is stored under high pressure
as compressed natural gas and hence called
CNG (Compressed Natural Gas).
Advantages
Natural gas is less pollu ng that’s why it is also
called clean fuel.
Its storage and transporta on is easy. It is sent
to far off places through the network of pipes.
Such a network of pipelines exists in Vadodara
(Gujarat). Some parts of Delhi and other places.
It is cheaper than petrol.
Uses
v Natural gas is now being widely used in
public transports especially buses, trucks
and auto- rickshaws.
v It is also used as Industrial fuel.
v It is also used as a star ng material for the
manufacture of a number of chemicals and
fer lizers.
Places of Occurrence
In India, natural gas has been found in Tripura,
Rajasthan, Maharashtra and in the Krishna-
Godavari delta.
ROLE OF ENERGY IN MODERN DEVELOPMENT
Energy plays such a vital role in our modern
development that we can say that energy is the
basis of modern development.
Let us study about its some important role, in
different sectors:
Industrial Sector
Most of the things that we use today are
manufactured in factories and industries. These
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