We use various materials of our basic needs. Some of them are natural and
some are manmade.
NATURAL RESOURCES
Those resources which are taken from nature are known as natural resources.
Types of natural resources
1. Inexhaustible natural resources
2. Exhaustible natural resources
Inexhaustible natural resources:
These resources are present in unlimited amount in nature and are not likely
to be exhausted by human activities.
Ex- sunlight, air, soil.
Exhaustible natural resources
They are in limited amount and it can be exhausted by human activities.
Ex- forest, minerals, coal etc.
Fossil Fuels
Some of the exhaustible natural resources like coal, petroleum, etc. are
formed by the dead remains of the living organisms. These kinds of
resources are known as fossil fuels.
COAL
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It is a hard like stone substance which is black in colour.
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It has many uses in various sectors.
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It was used as heat source to cook food, to produce steam to run train
and other engines, in thermal power plants to produce electricity etc.
Coal
Story of Coal
About 300 million years ago, there were dense forests existing on the
earth. As a result of some natural disasters like floods, these forests got
buried into the earth. Eventually, layers of soil got deposited over them
and they were compressed. The high pressure and temperature rose as they
sank deeper and deeper over this buried forest converted them into coal.
Carbonisation
The process of conversion of dead plants or vegetation into coal is called
as carbonisation.
It is being found that coal mainly contains the carbon and on burning in
air produces carbon dioxide gas.
Some products made from coals are:
(a) Coke:
It is tough, porous and black colour substance. It is the purest form of
carbon.
Uses: In manufacturing of steel, extraction of many metals, etc.
(b) Coal Tar
It is thick black colour liquid having unpleasant smell. It is a mixture of
about 200 substances.
Uses: The by-products obtained from coal tar are used in manufacturing of
synthetic dyes, drugs, explosives, perfumes, etc. Interestingly,
naphthalene balls used to repel moths and other insects are also obtained
from coal tar.
(c) Coal Gas
It is obtained during the coal is processed to obtain the coke.
Coal gas was used for street lighting for the first time in London in 1810
and in New York around 1820. Now days, it is used as a source of heat
rather than light.
Uses: It is mainly used as fuel in many industries.
PETROLEUM
Petrol is used as a fuel in light automobiles such as motor cycles and
cars. Many organisms were living in the seas. When these organisms died,
their bodies got settled at the bottom of the sea and got covered by layers
of sand and clay over them. After millions of years, the absence of air,
temperature and pressure converted them into petroleum.
Refining of Petroleum
Petroleum is a dark oily liquid and has unpleasant smell. It contains many
constituents like petroleum gas, petrol, diesel, lubricating oil, paraffin
wax, etc.
Process of refining petroleum:
Refining:
It is the process of separating the various constituents of petroleum and
it is carried out in a petroleum refinery.
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No.
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Constituents of petroleum
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Uses
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1
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Liquefied Petroleum Gas (LPG)
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As fuel for home and industry
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2
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Petrol
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As fuel for automobiles and as solvent for dry cleaning
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3
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Kerosene
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As fuel for stoves, lamps, etc.
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4
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Diesel
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As fuel for heavy motor vehicles, generators, etc.
|
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5
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Lubricating Oil
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For lubrication
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6
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Paraffin Wax
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In ointments, candles, Vaseline, etc.
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7
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Bitumen
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For making paints, surfacing roads, etc.
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Different constituents of petrol and their uses
3. Natural Gas:
(i) It is very important fossil fuel because it is easy and convenient to
send it through pipes.
(ii) In our country, natural gas has been found in Tripura, Rajasthan, and
Maharashtra and in the Krishna Godavari delta.
Compressed Natural Gas (CNG):
When natural gas is stored under high pressure it is termed as CNG.
Advantage
:
It causes less pollution. Moreover, it can be used directly at homes and
factories for burning and other purposes as it can be easily be transported
through pipes.
Application
It is used as fuel in automobiles.
It is used as a starting material for manufacturing of many chemicals and
fertilizers.
It is used as a starting material for manufacturing chemicals and
fertilizers.
Limitations of Natural Resources
Fossil fuels like coal, petroleum, etc. takes millions of years to get
converted from dead bodies to fuels. But, currently their demands are so
high that after few hundred years there will be scarcity of these
resources.
Moreover, too much of air pollution is caused dye to the burning of fossil
fuel. And these fuels are also responsible for the problems associated with
the global warming. Hence, it is important to use these fuels wisely and
carefully.
Some preventive measures to save fuels by Petroleum Conservation
Research Association (PCRA)
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Drive vehicles at constant and moderate speed.
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Switch off the engine at traffic lights or at a place where you have to
wait.
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Make sure pressure in tyres is correct.