NCERT Solutions for Class 8 Science Chapter 5 – Coal and Petroleum

Bitumen is the petroleum product used for surfacing roads.

 Mineral oil is made from the dead remains of plants and animals that were buried in the ground millions of years ago under high temperatures and pressure, which cannot be synthesized in the laboratory. Therefore, fossil fuels are a completely natural resource.

 Coke is a substance produced by the destructive distillation of coal. It is a grey, hard and porous fuel with high carbon content and few impurities. It is used to make steel and metal extraction as a reducing agent.

The advantages of using compressed natural gas (CNG) and liquified petroleum gas (LPG) as fuels is as follows:

1. They give a lot of heat energy when burnt as compared to other fuels like kerosene, coal, etc

2. They do not emit smoke when burnt, as they are clean fuels.

3. They have low prices.

4. They are easily available.

5. They can be easily transported by cylinders or pipelines.

Coal is made up of the remains of dead plants and animals buried in the ground, exposed to high temperatures and pressure in the absence of air. This process of the formation of coal is known as carbonization.

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 compressed natural gas (CNG).

a) False. Fossil fuels are made from the remains of dead plants and animals buried inside the earth millions of years ago and exposed to high temperature and pressure conditions.

b) False. CNG is an eco-friendly fuel and safe to use as it does not cause any health issues. Therefore, it is very less polluting.

c) True. Coke is a fuel with few impurities and high carbon content. That is why it is an almost pure form of carbon.  

d) True. Coal tar is a mixture of various substances such as dyes, paints, explosives, drugs, etc.

e) False. Kerosene is one of the products of the distillation of petroleum products.

Petroleum is made up of dead plant and animal fossils buried in the ground millions of years ago under high temperatures and pressure in the absence of air the dead remains are broken into smaller units to form petroleum and natural gas.

Plot the graph from the above data taking shortage percentage on the Y-axis and the year on the X-axis:

For example, for the year 

1991

1991

we mark the point

7.9

7.9

on the Y-axis.

Similarly, plotting the other points we get,