NCERT Solutions for CBSE Class 8 Science Chapter 5 – Free PDF Download

Free PDF download of NCERT Solutions Science Class 8 Solutions Chapter 5 – Coal and Petroleum solved by Expert Science Teachers on CoolGyan.Org. All Chapter 5 – Coal and Petroleum Questions with Solutions for NCERT to help you to revise complete Syllabus and Score More marks.
Science Revision Notes for Class 8

NCERT SOLVED

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

Ans. The advantage of using CNG and LPG are as follows:

• A non-polluting fuel for vehicles .
• These are used for power generation.
• These are used directly for burning in homes and factories.
• These are easily available.

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

Ans. A petroleum product ‘Bitumen’ is used for surfacing of roads.

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 earthquakes, floods and volcanic eruptions, these forests got buried under the soil. As more soil deposited over them, they were compressed. The temperature also raised as they sank deeper and deeper. Due to high temperature and lack of oxygen dead plants inside the earth got slowly converted to coal. This process of coal formation is called carbonization.

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) Coal, Petroleum and Natural gas.

(b) Refining

(c) CNG

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)

Ans. Tick True/false.

(a) F
(b) F
(c) T
(d) T
(e) F

6. Explain why fossil fuels are exhaustible natural resources.

Ans. Fossils fuels are limited in nature, and are liable to be exhausted by different human activities. So fossil fuels are called as exhaustible natural resources.

7. Describe characteristics and uses of coke.

Ans. 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 formation of petroleum.

Ans. 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 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.

Ans.