RBSE Solutions for Class 8 Science Chapter 5 Coal and Petroleum

Rajasthan Board RBSE Solutions for Class 8 Science Chapter 5 Coal and Petroleum Textbook Exercise Questions and Answers.

RBSE Class 8 Science Solutions Chapter 5 Coal and Petroleum

RBSE Class 8 Science Coal and Petroleum InText Questions and Answers

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Question 1. 
Can we use all our natural resources forever?
Answer:
No, we can not use all our natural resources forever. Natural resources like - forests, wildlife, minerals, coal, petroleum, natural gas are in limited amount in nature and can exhausted by human activities.

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Question 2. 
Where do we get coal from and how it is formed?
Answer:
Coal is obtained from Earth crust. Formation of coal - (Note - See the answer of Q. 3 in textbook Questions).

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Question 3. 
Can coal, petroleum and natural gas be prepared in the laboratory from dead organisms?
Answer:
No, coal, petroleum and natural gas can not be prepared in the laboratory from dead organisms because their formation is a very slow process and the conditions required for their formation can not be created in the laboratory.

RBSE Class 8 Science Coal and Petroleum Textbook Questions and Answers       

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

1. They do not create air pollution.
2. Combustion of them is almost complete.
3. No residue remains after burning of these gases.
4. They are comparatively cheap and easily available.
5. The ignition temperature of these gases is low.
6. It is easy to collect and transport these gases.
7. They can be used directly for burning in homes and factories where they can be supplied through pipes.

Question 2. 
Name the petroleum product used for surfacing of roads.
Answer:
Bitumen a petroleum product is used for surfacing of roads.

Question 3. 
Describe how coal is formed from dead vegetation. What is this process called?
Answer:
Coal was formed from the remains of vegetation (remains of plants) which were buried million years ago. These remains of vegetation got buried under the soil. As more soil and sediments deposited over them, they were compressed. 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.

Question 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 ....................   
Answer:
(a) coal, petroleum, natural gas
(b) refining 
(c) C.N.G. 

Question 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 from 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) F 
(b) F 
(c) T 
(d) T 
(e) F

Question 6. 
Explain why fossil fuels are exhaustible natural resources.
Answer:
Fossil fuels are formed from dead remains and this process takes millions of years. These resources are limited in nature and formation of these is very slow process while these are exhausted rapidly by human activities so fossil fuels are exhaustible natural resources. 

Question 7. 
Describe, characteristics and uses of coke.
Answer:
Characteristics of coke:

1. It is a tough, porous and black substance.
2. It is almost pure form of carbon.

Uses of coke:

1. Coke is used in the manufacture of steel and in the extraction of many metals.
2. Coke is used as a fuel. It burns without smoke so it is a good fuel.
3. Coke is also used in the preparation of gaseous fuels like water gas and producer gas. 

Question 8. 
Explain the process of formation of petroleum.
Answer:
Petroleum was formed by the decomposition of organisms (small plants and animals) living in the sea. As these organisms died, their bodies settled at the bottom of the sea and got cohered with layers of sand and clay. Over millions of years, absence of air, high temperature, high pressure and effect of bacteria as catalyst transformed the dead organisms into'hydrocarbons which is called petroleum. The formation of petroleum takes long time i.e. millions of years.

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.

Answer: