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SCIENCE CLASS 8


CHAPTER 5

COAL AND PETROLEUM

EXERCISES

Question no. 1

What are the advantages of using CNG and LPG as fuels?

Answer no. 1

There are so many advantages of using CNG and LPG as fuel
1. CNG and LPG are clean fuels and they do not release smoke, hence reduce the pollution.
2. CNG and LPG can be transported easily through pipelines.
3. CNG and LPG burn easily.
4. CNG and LPG gives a lot of heat energy when burnt.

Question no. 2

Name the petroleum product used for surfacing of roads.

Answer no. 2

Bitumen is used for surfacing of roads.

Question no. 3

Describe how coal is formed from dead vegetation. What is this process called?

Answer no. 3

The earth had dense forests in low lying wetland areas. Due to natural processes, such as flooding, these forest got buried under the soil. More and more soil got deposited over them and and they got compressed more. The temperature also rose as they went deeper and deeper. Under high pressure and high temperature, dead plants got slowly converted to coal.
            The process of conversion of dead vegetation into coal is called carbonisation.

Question no. 4

Fill in the blanks:
(a) Fossil fuels are ___________, __________ and ___________.
(b) Process of separation of different constituents from petroleum is called __________.
(c) Least polluting fuel for vehicle is ___________.

Answer no. 4

(a)coal, petroleum, natural gas
(b)refining
(c)compressed natural gas (CNG)

Question no. 5

Tick True/False against the following statements:
(a) Fossil fuels can be made in the laboratory. (T/F)
(b) CNG is more polluting fuel than petrol. (T/F)
(c) Coke is almost pure form of carbon. (T/F)
(d) Coal tar is a mixture of various substances. (T/F)
(e) Kerosene is not a fossil fuel. (T/F)

Answer no. 5

(a)False
(b)False
(c)True
(d)True
(e)False

Question no. 6

Explain why fossil fuels are exhaustible natural resources.

Answer no. 6

The process of formation of fossil fuels requires millions of years. Dead vegetation get buried deep inside the earth and requires high pressure and temperature to get converted into fossil fuel. It cannot be manufactured in factory or laboratory so it is limited in nature. Hence the use of fossil fuels rapid rate will lead to then exhaustion.

Question no. 7

Describe characteristics and uses of coke.

Answer no. 7

Characteristics of coke

1. It is tough
2. It is is porous
3. It is black in colour
4. It is an almost pure form of carbon

Uses

1. It is used in the manufacturing of steel
2. It is used in the extraction of metals
    (As a reducing agent)

Question no. 8

Explain the process of formation of petroleum.

Answer no. 8

Petroleum was formed from organism living in the sea. As these organisms die, their bodies settled at the bottom of the sea and got covered with layers of sand and clay. Over the million of years due to absence of air, high temperature and high pressure dead organism are transformed into petroleum and natural gas.

Question no. 9

The following Table shows the total power shortage in India from 1991– 1997. Show the
data in the form of a graph. Plot shortage percentage for the years on the Y-axis and the
year on the X-axis.

Answer 




ALSO SEE SOLUTIONS OF FOLLOWING CHAPTERS :

 Crop Production And Management
Microorganisms - Friend And Foe
Synthetic Fibre And Plastic

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