CLASS 8 Chapter 5 Coal and Petroleum

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

Solution 1.  The following are the advantages of using compressed natural gas (CNG) and liquid petroleum gas as fuels;

• They have low prices
• They are easily available.
• They do not cause any pollution as they burn with smokeless flame.
• They leave no ash on burning.
• It is very easy to handle CNG and LPG.
• They are very convenient to store.

Question 2. Name the petroleum product used for surfacing roads.
Solution 2.  Bitumen is used for the surfacing of roads.

Question 3. Describe how coal is formed from dead vegetation. What is this process called?
Solution 3.  Dead remain of trees, plants, ferns and forests got buried below the rocks, soil and sand due to some natural processes like flooding, earthquake, etc. due to the deposition of soil over the period of time these dead remains were compressed. This led to the conditions of high pressure and heat. These conditions of high pressure and high temperature along with the anaerobic conditions turned the carbon-enriched organic matter of wood into coal.
This slow process of conversion of wood into coal which mainly contains carbon is called carbonisation.

Question 4.
Fill in the blanks.
(a) Fossils fuels are ____ , ____ and ____
(b) Process of separation of different constituents from petroleum is called ______
(c) Least polluting fuel for vehicle is ______
Answer:
(a) Fossil fuels are coal, petroleum and natural gas.
(b) Process of separation of different constituents from petroleum is called refining.
(c)  Least polluting fuel for vehicles is CNG.

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

(b) CNG is more polluting fuel than petrol. False
(c) Coke is an almost pure form of carbon. True

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

(e) Kerosene is not a fossil fuel. False

Question 6. Explain why fossil fuels are exhaustible natural resources.
solution 6.  Exhaustible natural resources are those resources which are limited in nature Fossil fuels are one of them. Fossil fuels are limited in nature and cannot be replenished easily, once consumed. Hence, fossil fuels are considered exhaustible natural resources.

Question 7. Describe the characteristics and uses of coke.
Solution 7.  Characteristics of coke:

• Coke is almost 98% pure carbon.
• coke is a tough, porous and black substance.
• It produces very little smoke.

Uses of coke:

• Coke is very useful as fuel.
• It is a good reducing agent.
• It is widely used in metallurgical processes to reduce metals from their oxides.
• It is used for producing water gas.

Question 8. Explain the process of the formation of petroleum.
Solution 8.  Petroleum is formed by the burial of aquatic plants and animals below the sea bed. The marine animals and plants died thousands of years ago and settled down in the bottom of the sea. In anaerobic conditions, this organic matter is decomposed by the microorganism. Due to the absence of oxygen and high pressure and heat, the dead remains of tiny plants and animals are slowly converted into petroleum.

Question 9. The following table shows the total power shortage in India from 2004-2010. Show the data in the form of a graph. Piet shortage percentage for the years on the y-axis and the year on the x-axis.