This document provides information about coal and petroleum as natural resources. It discusses how coal and petroleum are exhaustible natural resources that are formed from the remains of ancient living organisms. Coal forms over millions of years from dead plant matter buried underground. It is mined and used mainly as fuel for electricity generation or in the past for steam engines. Petroleum forms similarly from marine organisms and is extracted through drilling, then refined to produce fuels like petrol and diesel. Both coal and petroleum are fossil fuels that are finite and their combustion contributes to issues like global warming.

1. Self Learning Material
Class : 8 (CBSE)
Sub: Science
By Avani Panchal
Bed: 2014/015
Id No: 14162057

3. Coal and Petroleum
Natural Resources: Resources, which are obtained from nature, are called natural
resources. Some natural resources can be used directly, while using some others we
need the help of some technology .for example given in below fig…
Inexhaustible Natural Resources: Resources which do not exhaust and which
are available in plenty in nature are known as inexhaustible natural resources. For
example – air, sunlight, etc
.

4. Exhaustible Natural Resources: Resources which get exhausted and are not
available in nature in plenty and are known as exhaustible natural resources. They take
longer to get replenished. For example – coal, petroleum, forest, minerals, etc.
Coal and Petroleum: Coal and petroleum are exhaustible natural resources as their
availability is limited in nature. Coal and petroleum are used mainly as fuel. Coal is used
as fuel, petroleum products are used to run vehicle and for many other purposes. Coal
and petroleum are known as fossil fuels since they are formed from remains of
living organism.
Coal
Coal is a black coloured stone-like material. Coal is used to produce electricity in
thermal power stations. Coal was used to run steam engine till recent years in India.
Coal gives carbon dioxide when burnt in air.
C + O2------------> CO2
Formation of Coal
About 300 millions year ago, dense forest in low lying lands of earth got buried because
of many natural processes. In the due course, they sank deeper and deeper. Inside the
earth, because of high pressure and temperature they slowly converted into coal. Such
slow process of conversion of dead vegetation into coal is called carbonization.
Coal is considered as fossil fuel as it is formed because of
carbonization of dead remains of living organism. Coal is
mined from earth and processed to obtain many useful
products, such as coal,coke, coal tar, etc

5. Coke
Coke is almost pure form of carbon. Coke is a porous, black and
similar to coal. Coke has high percentage of carbon and very low
percent of impurities. It is obtained from destructive distillation of
a particular type of coal. Coke is used as fuel, as reducing agent
in the smelting of iron ore in blast furnace. It is used in the
manufacturing of steel and in the extraction of many types of
metals.
Coal Tar
Coal tar is obtained as one of the by-products while obtaining the coke or coal gas. Coal
tar is a highly viscous liquid and brown-black in colour. It is a variable mixture of many
substances.
Coal tar is used in the manufacturing of many
products; such as synthetic dyes, drugs,
explosive, perfumes, plastics, roofing material,
etc. as starting material.
Till about two decades ago, coal tar was used
as binding material in the making of roads.
Now-a-days bitumen is used in making of
roads in the place of coal tar.
Coal gas
Coal gas is also one of the by-products in the processing of coke. Coal gas is used as
fuel mainly for heating in many industries.
Followings the different types of Coal:
1. Lignite (Brown Coal) contains 25 – 35 % carbon.
2. Bituminous coal (Soft coal) contains 45 – 86 % carbon.
3. Anthracite coal (Hard coal – It has the highest heat energy) contain 87 – 97%carbon.

6. Petroleum
The word petroleum is used for both naturally occurring crude oil and other petroleum
products, which are obtained after refining of crude oil, such as petrol, diesel, etc. Petrol
and diesel are highly consumed fuel today as these are used to run vehicles.Petroleum
is a dark oily liquid having unpleasant odor.
Formation of Petroleum
Petroleum is formed from the dead remains of living organisms which lived in sea and
were buried millions of year ago below the sea bed. Because of high pressure and
temperature those dead remains were transformed into petroleum. Since, petroleum is
the product of dead remains, so it is known as fossil fuel.
Extraction of petroleum
Petroleum is extracted from the reservoir
usually found in sea beds and river basin by
drilling through pipe lines. Such places where
reservoir of petroleum are found and extracted
out by drilling are known as oil well.
Refining of Petroleum
After extraction, petroleum is refined to obtain petrol, diesel, lubricating oil, wax,
paraffin, bitumen, kerosene, etc. Place where refining process of petroleum is done is
called petroleum refinery.
Oil drillingmachine

7. Some of the petroleum products and their uses
Petroleum products Uses
Petrol Fuel in motor car, aviation, solvent for dry cleaning
Diesel
Fuel for heavy vehicle, such as trucks, rail engine, small
vehicle, such as jeep car, for jet air crafts, small
generators, etc.
Liquid Petroleum Gas Fuel in households, and in vehicles.
Kerosene Fuel for stoves, jet aircrafts, lamps, etc.
Lubricating oil Used as lubricants mainly in engines.
Paraffin wax
Used in manufacturing of ointment, candles, cosmetics,
etc.
Bitumen Used in making of paints, road, etc.
Natural Gas
Natural gas is naturally occurring hydrocarbon gas. Natural gas is a mixture of methane,
higher alkanes, carbon dioxide, etc. Natural gas is found in deep underground rock
formation as fossil fuel. It is one of the most important fuel.
Natural gas can be transported through pipeline and can be compressed to smaller
volume. Compressed natural gas (CNG) is used for running vehicle. Natural gas can be
used directly for burning as fuel. It is a clean fuel as it creates least pollution.
Natural gas is used as starting material in many industries, such as fertilizer and
chemical.
In India natural gas reserves are found in Tripura, Rajasthan, Maharashtra, and Krishna
and Godavari delta.
The advantages of CNG and LPG fuels are :
 they have high calorific value
 They can be transported easily through pipelines.
 They are clean fuels and do not give smoke when burnt.
 they burn without producing any smoke

8. Harmful effects of burning fossil fuels: How it affect the environment?
 The increases in carbon dioxide lead to large scale environmental damage such
as acid rain.
 Carbon dioxide that the remains in the upper atmosphere will tend to trap sun
rays, which is called the "greenhouse effect" and leads to global warming.
 People can become sick from breathing carbon monoxide emitted from vehicles.
 Burning of coal releases sulfur and nitrogen, which help form acid rain.
Some Natural Resources are Limited
Petroleum, coal, natural gas, etc. are natural resources but available in limited
amount. Thus, it is necessary to use them with care.
Some steps to conserve fossil fuels (Natural Resources):
 Switch off the engine of vehicle when waiting on signals or at other places.
 Drive the vehicle with constant and moderate speed.
 Maintain the correct tyre pressure for low consumption of fuel.
 Maintain the vehicle by regular checking to ensure less consumption of fuel

9. Exercise
1. What are the advantages of using CNG and LPG as fuels?
Ans:
2. Explain why fossil fuels are exhaustible natural resources.
Ans.
3.Describe characteristics and uses of coke.
Ans.