NCERT Solutions for Class 8 Science Chapter 5 Coal and Petroleum

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Coal and Petroleum NCERT Solutions for Class 8 Science Chapter 5

Class 8 Science Chapter 5 Coal and Petroleum Exercise Questions and Answers

Question 1.
What are the advantages of using CNG and LPG as fuels?
Answer:
The advantages of using CNG and LPG as fuel are:

1. A non-polluting fuel for vehicles.
2. It is used for power generation.
3. It can be used directly for burning in homes and factories.
4. They are easily available.

Question 2.
Name the petroleum product used for surfacing roads?
Answer:
These days bitumen, a petroleum product is used for surfacing the roads in place of coaltar.

Question 3.
Describe how coal is formed from dead vegetation. What is this process called?
Answer:
About 300 million years ago the earth had dense forests in low-lying wetland areas. Due to natural calamities, 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, which mainly contains carbon. The slow process of conversion of dead vegetation into coal is called carbonization.

Question 4.
Fill in the blanks.
(a) Fossil fuels are ______ , ______ and ______.
Answer:

1. Coal
2. Petroleum
3. Natural gas

(b) Process of separation of different constituents from petroleum is called ______.
Answer:
Refining

(c) Least polluting fuel for vehicle is ______.
Answer:
CNG (compressed natural gas)

Question 5.
Tick True/False against the following statements:

(a) Fossil fuels can be made in the laboratory.
Answer:
False

(b) CNG is a more polluting fuel than petrol.
Answer:
False

(c) Coke is an almost pure form of carbon.
Answer:
True

(d) Coal tar is a mixture of various substances.
Answer:
True

(e) Kerosene is not a fossil fuel.
Answer:
False

Question 6.
Explain why fossil fuels are exhaustible natural resources?
Answer:
Fossil fuels are limited in nature and are liable to be exhausted by different human activities so they are called exhaustible natural resources.

Question 7.
Describe the characteristics and uses of coke.
Answer:
Coke is a tough, porous, and black substance. It is an almost pure form of carbon. It is used in the manufacture of steel and in the extraction of many metals.

Question 8.
Explain the process of the formation of petroleum.
Answer:
Petroleum occurs deep down in the earth between the layers of non-porous rocks. Crude oil, i.e., petroleum is formed by the decomposition of animal and plant remains over millions of years under the earth. Natural gas occurs above the layer of petroleum oil i.e., trapped under the rocks.

Question 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

Answer:

Class 8 Science Chapter 5 Coal and Petroleum InText Questions and Answers

Activity 5.1

Question 1.
Make a list of various materials used by us in daily life and classify them as natural and man-made.
Answer:

Natural	Man-made
Water	Plastic
Sunlight	Rubber
Air	T.V.
Soil	Refrigerator
Coal	Lassi
Petrol	Pen
LPG	Bed
CNG	Car
Minerals	Bicycle
Fruits	Toffees

Question 2.
Does this list- include air, water, soil, and minerals?
Answer:
Yes, these are included in the list.

Question 3.
Can we use all our natural resources forever?
Answer:
Some natural resources are going to exhaust one day. So we cannot use them forever.

Question 4.
Can air, water, and soil be exhausted by human activities?
Answer:
No, these will not be exhausted by human activities.

Question 5.
Is water a limitless resource?
Answer:
Yes, water is a limitless source, but its unwise use and cutting of forest can also make its usable form scarce.