NCERT Solutions for Class 8th Science

Chapter 5 – COAL AND PETROLEUM

(Complete Downloadable Chapter Solution PDF file is at the bottom of the page)

 

Q.1       What are the advantages of using CNG and LPG as fuels?

Ans     The advantages of using CNG and LPG as fuels are:

            1) They are cleaner fuel and cause less pollution.

            2) They are easy to transport through pipes.

            3) They can be used directly for burning in homes and factories.

            4) They have high calorific value.

Q.2       Name the petroleum product used for surfacing of roads.

Ans      Bitumen

Q.3       Describe how coal is formed from dead vegetation. What is this process called?

Ans     About 300 million years ago the earth had dense forests in low lying wetland areas. Due to natural                         processes, like flooding, these forests got buried under the soil. As more soil deposited over them, they                   were compressed. The temperature also rose as they sank deeper and deeper. Under high pressure and                 high temperature, dead plants got slowly converted to coal.

            As coal contains mainly carbon, the slow process of conversion of dead vegetation into coal is called                       carbonisation. Since it was formed from the remains of vegetation, coal is also called a fossil fuel.

Q.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 __________.

Ans     (a) Fossil fuels are _coal_, _petroleum_ and _natural gas_.

Q.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)

Q.6      Explain why fossil fuels are exhaustible natural resources.

Q.7      Describe characteristics and uses of coke.

Q.8      Explain the process of formation of petroleum.

Q.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.

S. No.        Year      Shortage (%)

1                 1991           7.9

2                 1992          7.8

3                 1993          8.3

4                 1994          7.4

5                 1995          7.1

6                 1996          9.2

7                 1997          11.5