NCERT Solutions Class 8 Science Chapter 5 Coal and Petroleum

NCERT Solutions Class 8 Science 

The NCERT Solutions in English Language for Class 8 Science Chapter – 5 (Coal and Petroleum) has been provided here to help the students in solving the questions from this exercise.

Chapter – 5 (Coal and Petroleum)

1. What are the advantages of using CNG and LPG as fuels?
Answer – The advantages of using compressed natural gas (CNG) and liquified petroleum gas (LPG) as fuels are:

• They can be burnt directly.
• They can be transported easily through pipelines.
• They are clean fuels and do not give smoke when burnt.
• They give a lot of heat energy when burnt.

2. Name the petroleum product used for surfacing of roads.
Answer –  Bitumen, a petroleum product, is used for surfacing roads.

3. Describe how coal is formed from dead vegetation. What is this process called?
Answer –  Millions of years ago, there were dense forests on earth in low lying areas Due to floods, earthquakes, volcanoes, etc., the forest got buried in soil As more and more soil deposited over them, they sank deeper Due to high temperature and pressure inside the earth, and the due to no air inside the earth, the dead plants and trees got slowly converted into coal. This process of conversion of dead plants and trees into Carbon is called Carbonization.

4. Fill in the blanks.
(a) Fossil fuels are  ____________,  ____________, and ____________ .
(b) The process of separation of different constituents from petroleum is called _____________ .
(c) The least polluting fuel for a vehicle is ______________ .

Answer –
(a) Fossil fuels Coal, Petroleum, and natural gas.
(b) The process of separation of different constituents from petroleum is called refining.
(c) The least polluting fuel for a vehicle is Compressed Natural Gas (CNG).

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

6. 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.

7. Describe the characteristics and uses of coke.
Answer – Characteristics of coke are:

• Tough
• Porous
• Black in colour
  

Uses of coke:

• In manufacture of steel.
• In the extraction of metals (as a reducing agent).

8. Explain the process of the 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.

9. The following table shows the total power shortage in India from 1993–1999. 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 –