NCERT Solutions for Class 8 Science Chapter 3 Coal and Petroleum

NCERT
SOLUTIONS
CLASS - 8TH

aglase .co

Book : Science Ncert Solutions | Chapter-5 Science

Class : 8th
Subject : Science
Chapter : 5
Chapter Name : COAL AND PETROLEUM

Q1 What are the advantages of using CNG and LPG as fuels?

Answer. The advantages of using compressed natural gas (CNG) and liqui�ed petroleum
gas (LPG) as fuels are:
(i) They can be burnt directly.
(ii) They can be transported easily through pipelines.
(iii) They are clean fuels and do not give smoke when burnt.
(iv) They give a lot of heat energy when burnt.

Q2 Name the petroleum product used for surfacing of roads.

Answer.Bitumen, a petroleum product, is used for surfacing roads.

Q3 Describe how coal is formed from dead vegetation. What is this process called?

Answer. Millions of years ago, dense forests got buried under the soil due to natural
processes like storms, �oods, and earthquakes. These got compressed as more and more
soil got deposited over them. When they got buried deep in the soil, they were exposed to
very high pressure and temperature. Under these conditions, these slowly got converted
into coal. This process of formation of coal from dead vegetation is called carbonization.

Q4 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. (a) Fossil fuels are coal, petroleum and natural gas
(b) Process of separation of different constituents from petroleum is called re�ning

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Book : Science Ncert Solutions | Chapter-5 Science

(c) Least polluting fuel for vehicles is compressed natural gas (CNG)

Q5 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. (a) Fossil fuels can be made in the laboratory. (F)
(b) CNG is more polluting fuel than petrol. (F)
(c) Coke is almost pure form of carbon. (T)
(d) Coal tar is a mixture of various substances. (T)
(e) Kerosene is not a fossil fuel. (F)

Q6 Explain why fossil fuels are exhaustible natural resources.

Answer. Fossil fuels require millions of years to form from the dead vegetation and
animals that get buried deep inside the Earth. They require high temperature and
pressure for their formation, which cannot be provided in the laboratory. Thus, fossils
are limited. Therefore, the use of fossil fuels at this rate will lead to their exhaustion.

Q7 Describe characteristics and uses of coke.

Answer. Characteristics of coke are:
(i) Tough
(ii) Porous
(iii) Black in colour
Uses of coke:
(i) In manufacture of steel.
(ii) In the extraction of metals (as a reducing agent).

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Book : Science Ncert Solutions | Chapter-5 Science

Q8 Explain the process of formation of petroleum.

Answer.Petroleum was formed from dead organisms that got buried in the sea millions of
years ago. These dead bodies got covered with layers of sand and clay. Lack of air, high
temperature, and high pressure transformed these dead organisms into petroleum and
natural gas.

Q9 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.

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