Coal and Petroleum Class 8 Notes Science Chapter 3 (old chapter -5 )
Natural
Resources: The
resources, that are obtained from nature are called natural resources, for
example, air, water, soil and minerals.
Inexhaustible Natural Resources: The resources, that are present
in unlimited quantity in nature, and cannot be exhausted by human activities,
for example, air, sunlight etc.
Exhaustible Natural Resources: The resources, that are present
in limited quantity in nature, and can be exhausted by human activities, for
example, coal, petroleum, minerals, forests etc.
Fossil: The remains of the part of
plants or animals transformed over time, is called fossil.
Some exhaustible natural resources from the dead remains of
living organisms are known as fossil fuels, for example, coal, petroleum and
natural gas.
Coal is a fossil fuel, that was formed by the decay of
vegetation, which existed millions of years ago. It is a non-crystalline form
of carbon.
Carbonisation: The slow process of conversion
of dead vegetations into coal is called carbonisation.
Coke is an amorphous form of carbon, which is harder and denser
than charcoal and is used as a fuel. It is obtained by heating soft coal in the
absence or little supply of air. It is black in colour. It is used in the
manufacture of steel.
Destructive Distillation: The process of heating coal in
the absence of air is called destructive distillation.
Coal Tar is a black thick liquid, i.e., a mixture of about 200
substances and is used to get various materials of everyday life/industry,
like; drugs, dyes, plastics, perfumes, paints, naphthalene balls etc.
Coal Gas is a by-product, that is obtained during the processing
of coal to form coke, and is used as a fuel.
Petroleum is a fossil fuel, that is obtained by the
decomposition of dead animals and plants due to geological changes under the
earth. It means oil from the rocks. It is a dark oily liquid that is insoluble
in water.
Various constituents of petroleum and
their uses are as follows:
|
S. No. |
Constituents
of Petroleum |
Uses |
|
1. |
Petroleum
Gas in Liquid form (LPG) |
Fuel
for home and industry |
|
2. |
Petrol |
Motor
fuel, aviation fuel, solvent for dry cleaning |
|
3. |
Kerosene |
Fuel
for stoves, lamps and for jet aircrafts |
|
4. |
Diesel |
Fuel
for heavy motor vehicles, electric generators |
|
5. |
Lubricating
oil |
Lubrication |
|
6. |
Paraffin
wax |
Ointment,
candles, vaseline etc. |
|
7. |
Bitumen |
Paints,
road surfacing |
Petroleum Refining: The process of separating the
different constituents/fractions of petroleum is known as petroleum refining.
Natural Gas is a very important fossil fuel, that is stored
under high pressure and is easy to transport through pipes and referred to as
CNG (compressed natural gas). It is a non-polluting fuel. It helps in the
manufacture of a number of chemicals and fertilizers.
Coal: Coal is a fossil fuel, formed by
the decay of vegetation which existed millions of years ago.
Coal Gas: Coal gas is obtained as a
by-product during the processing of coal to form coke, and is used as a fuel.
Coal Tar: It is a black thick liquid with
an unpleasant smell obtained by the processing of coal.
Coke: It is tough, porous and black
substance obtained by the processing of coal.
Fossil Fuel: Dead remains of living organisms
and buried over millions of years, like coal, petroleum and natural gas are
fossil fuels.
Natural Gas: Natural Gas is a very important
fossil fuel. It is a cleaner fuel.
Petroleum: It is a dark oily liquid with an
unpleasant odour. It is a source of petrol and diesel.
Petroleum Refinery: Petroleum refinery is a place where the process of separating the various constituents of petroleum is carried out.
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