Class 08 (Science)
Chapter 05
Coal and petroleum
Natural resources - Resources include everything provide by the
nature. They form wealth of country.
It can be
classified into types
(1) Inexhaustible natural resources- These resources are
present in unlimited quantity in nature and are not likely to exhausted by
human activities.
Ex. Sunlight, air
(2) Exhaustible
natural resources- The amount of these resources in
nature is limited. They can be exhausted by human activities.
Ex. Forests, wildlife, minerals, coal, petroleum, natural gas etc
Fossil fuels- This type of fuel formed from the dead remains of living organisms
(fossils). So it is known as fossil fuels.
Ex. Petroleum, coal and natural gas
Coal- It is as hard as stone and black
in colour.
* It is one of
the fuels use to cook food
* It was used
in railway engines to produce steam to run the engine.
* It is used
in thermal power plants to produce electricity.
* It also
used as a fuel in various industries.
Coal contains mainly carbon,
the slow process of conversion of dead vegetation into coal is called
carbonisation.
When heated in air, coal
burns and produced mainly carbon dioxide.
Coal is processed in industry to get some useful products like coke, coal
tar and coal gas.
Coke- It is tough, porous and black substance. It is
almost pure form of carbon. It is used in the manufacture of Steel and in the
extraction of many metals.
Coal tar - It is a black, thick liquid with
an unpleasant smell. It is a mixture of about 200 substance. It is used
manufacturing of synthetic dye, drugs, explosives, perfumes, plastic, pants,
photographic materials etc.
Coal gas - It is obtained during the
processing of coal to get coke. it is used as a fuel in many industries
situated near the coal processing plant.
Petroleum > Petra =Rock
Oleum = oil
Petrol and diesel are obtained from a natural source called petroleum.
* Petrol is
used as a fuel in light automobiles such as motorcycles, scooters and trucks.
Heavy vehicle run on diesel.
* It is mined
from between the rocks under Earth.
Petroleum was formed from organisms living in the sea. These organisms
died, their bodies settled at the bottom of the sea over millions of years,
absence of air, high pressure and high temperature transformed the dead
organisms into petroleum and natural gas.
Refining of
petroleum - Petroleum is a dark oily liquid. It has an unpleasant order.
* It is a mixture of various
constituents such as petroleum gas, petrol, diesel, lubricating oil, paraffin
wax etc
* The process of separating the
various constituents/fractions of petroleum is known as refining.
=> Many useful substances are
obtained from petroleum and natural gas. These are termed as
"petrochemicals"
It is used in the
manufacturing of detergents, fibres. Polythene, plastic, fertilizers etc.
* Petroleum is also called 'black
gold'
Natural gas - It is very important fossil fuel because it is easy to transport through
pipes.
* It is stored under high pressure as compressed natural gas ( CNG )
* CNG is used for power
generation.
* It is now being used as fuel for
transport vehicles.
Some natural
resources are limited - Some natural resources are
exhaustible like fossil fuels, forests, minerals etc. we use these fuels only
when absolutely necessary. This will result in better environment, smallest risk
of global warming and their availability for a longer period of time.
Constituent of petroleum
|
Uses
|
Petroleum gas in liquid form (
LPG)
|
Fuel for home and industry
|
Petrol
|
Motor fuel, aviation fuel,
solvent for dry cleaning
|
Kerosene
|
Fuel for stoves, lamps and for
Jet aircrafts.
|
Diesel
|
Fuel for heavy motor vehicle,
electric generators.
|
Lubricating oil
|
Lubrication
|
Paraffin wax
|
Ointment, candles, Vaseline.
|
Bitumiin
|
Paints, Road surfacing
|
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