Revision Notes For CBSE Class 8 Science Chapter 5 - Coal And Petroleum

Natural Resources:

• Everything that nature provides is considered a natural resource. 

• They contribute to a country's economy.

• Natural resources can be broadly categorised into two types based on the abundance of various resources in nature:

1. Inexhaustible Natural Resources:

• These resources are abundant in nature and are unlikely to be exhausted as a result of human activities.

• Sunlight and air are two examples.

2. Exhaustible Natural Resources:

• These resources are scarce and can quickly become depleted if they are overused. 

• Forests, wildlife, minerals, coal, petroleum, and other natural resources are the examples.

Fossil Fuels:

• Coal, petroleum, and natural gas are examples of non-renewable natural resources.

• Millions of years ago, fossil fuels were produced from the dead remains of live species.

• Fossil fuels are finite resources that cannot be replenished.

Coal:

• Coal is a black substance that is as hard as stone.

• One of the fuels used to prepare food is coal.

• It was once utilised in railway engines to generate steam to power them.

• It's also utilised to generate electricity in thermal power plants.

• Coal is also employed as a source of energy in a variety of sectors.

• Dead plants were slowly transformed to coal under intense pressure and high temperature. 

• Carbonisation is the lengthy process of converting dead plants into coal, because coal is primarily made up of carbon. 

• Coal is classified as a fossil fuel since it was created from the leftovers of plants.

• When coal is burned in the presence of air, it burns and produces primarily carbon dioxide gas.

• In industry, coal is processed to produce useful products such as coke, coal tar, and coal gas.

Coke:

• It's a dark, rough, porous substance. 

• It's a carbon that's practically completely free of impurities. 

• Coke is utilised in the production of steel as well as the extraction of a variety of metals.

Coal Tar:

• It's a dark, thick liquid with an obnoxious odour. 

• It's made up of almost $200$ different chemicals. 

• Coal tar is used as starting materials for the manufacture of various substances used in everyday life and industry, such as synthetic dyes, drugs, explosives, perfumes, plastics, paints, photographic materials, roofing materials and so on.

• Coal tar is also used to make naphthalene balls, which are used to repel moths and other insects.

• Bitumen, a petroleum product, is now used to metalize roads in place of coal tar.

Coal Gas:

• Coal gas is created when coal is processed to make coke. 

• Many companies near coal processing plants use it as a source of energy.

• For street illumination, coal gas was employed.

• It is now employed as a heat source rather than a light source.

Petroleum:

• Petrol and diesel are made from petroleum, a natural resource.

• Petroleum is formed from the words petra (rock) and oleum (oil) since it is obtained from between the rocks beneath the Earth.

• Petroleum is made up of organisms that live in the water. 

• When these organisms perished, their remains sank to the seafloor and were covered in layers of sand and clay. 

• The absence of air, high temperature, and high pressure turned the dead organisms into petroleum and natural gas over millions of years.

Refining of Petroleum:

• Petroleum is a thick, viscous liquid with a dark colour. 

• It has an unpleasant odour. 

• It is made up of a variety of ingredients such as petroleum gas, gasoline, diesel, lubricating oil, paraffin wax, and so on.

• Refining is the process of separating the various constituents/fractions of petroleum. 

• It takes place in a petroleum refinery.

The Following Table Gives Details About Petroleum Constituents and Their Applications.

• Petroleum and natural gas are used to make a variety of useful compounds. These are also called as Petrochemicals.

• They are used in the manufacturing of products like Detergents, fibres (polyester, nylon, acrylic, etc. ), polythene, and other man-made polymers. 

• Fertilizers are made from hydrogen gas, which is derived from natural gas (urea).

• Petroleum is sometimes known as "black gold" due to its high commercial value.

Natural Gas:

• Compressed Natural Gas is a very essential fuel since it is easy to transfer through pipes and can be compressed and stored under high pressure. 

• It does not pollute the environment and has a high calorific value.

• CNG is utilised to generate electricity. 

• It is now used as a transportation vehicle fuel.

• It is a cleaner fuel.

• Natural gas is also utilised as a raw material in the production of a wide range of chemicals and fertilisers.

• India has enormous natural gas reserves. 

• Natural gas has been discovered in Tripura, Rajasthan, Maharashtra, and the Krishna Godavari delta in our country.

• The availability of coal and petroleum is restricted. We should use them with caution.

• The Petroleum Conservation Research Association (PCRA) in India offers tips on how to save petrol and diesel when driving.

The Following are Their Recommendations: 

1. Drive at a consistent and moderate speed as far as feasible; 

2. Turn off the motor at traffic signals or other places where you must wait; 

3. Maintain proper tyre pressure.

4. Ensure that the car is maintained on a regular basis.

A Brief Overview of Class 8 Science Chapter 5 Coal And Petroleum

Introduction to Coal

Coal is a fossil fuel, black in color. It is extracted from the earth and it is used for various purposes.

Uses of Coal

Coal is Used for Several Purposes Like

• Activated charcoal is used to make face packs and cosmetics.

• Thermal coal is used for the generation of electricity.

• Coking coal is used for the production of steel.

Coal and Coke

What is Coal?

Coal is a black sedimentary rock that forms in coal fields and coal mines. From these coal beds and mines, coal is extracted. Its formation takes millions of years. It happens naturally.

What Is Coke?

Coal along with a very high carbon content also has a few impurities called coke in it. Coke which is present in the solid-state comprises components that arise as a result of the destructive distillation of low-ash low-sulfur bituminous coal, extracted from carbonaceous material and is typically a grey, brittle, and hard substance found in nature. It is sometimes referred to as pet coke or coke with petroleum.

Uses of Coke

• It can be used as a clean fuel in homes, as it is relatively free from smoke.

• Coke is also used to generate gas from water.

• In smelting iron ore, it is used as a reduction agent.

• It is also used by blacksmiths as a fuel.

Coal Gas and Coal Tar

What is Coal gas?

Coal gas is a combination of hydrogen, methane, carbon monoxide, and volatile hydrocarbons formed by destructive coal distillation. It is a flammable gas and is produced from coal supplied by a piped system.

Uses of Coal Gas

• Coal gas is used in lighting.

• It is used as a fuel.

• Coal gas is also used as an illuminant.

What is Coal Tar?

Coal tar is a dark black liquid that is a by-product of coal-gas and coke production. It includes organic chemicals such as benzene, naphthalene, phenols, aniline, and many others. For medical and industrial purposes, coal tar is used.

Uses of Coal Tar

• Coal tar is used to cover the underlying pavement and to beautify it.

• Coal is also used to produce seal-coat items for parking lots.

• Roads are manufactured using coal tar.

• Coal tar, in nature, is flammable. Hence for heating, it is used.

Natural Gas

What is Natural Gas?

Natural gas is a combustible fossil fuel. It occurs naturally and consists of around 95 percent hydrocarbon methane, with nitrogen, carbon dioxide, helium or hydrogen sulfide being the other 5 percent. For it to form, it takes millions of years.

Uses

• It is used in vehicles in the form of CNG (Compressed Natural Gas).

• It is used as a chemical feedstock for rubber and plastic processing. 

• Gas is also useful in the manufacture of garments, glass, paint, etc. 

What is Petroleum?

Petroleum is a naturally occurring substance. It's a black liquid. It exists under the surface of the earth. A significant number of goods, such as petrol, diesel, lubricating oil, etc., are derived from petroleum. Its compounds can be isolated by fractional distillation.

The Formation of Petroleum

Petroleum takes about millions of years to develop. These dead animals' carcasses are subjected to intense pressure and heat. Over the years, millions of animals have lived and died to become fossilized, just like the case of plant-based matter.

The decomposed organic matter has been buried deeper and deeper through the years due to the presence of bacteria. For millions of years, high temperatures, high pressure, and the lack of air have turned dead animals into petroleum and coal.

Petroleum, or crude oil, is this liquefied form of dead organic matter. Deep wells are used to get crude oil from nature. This crude oil is then processed and refined to create various petroleum products that we use. For example petrol, diesel, lubricants, kerosene, and many others.

Fun Facts About the Products Produced in the Petroleum Refining Process

Did you know that during the petroleum refining process, we don’t just get petroleum gas but other products too? Gasoline and Kerosene, which is a domestic fuel option, are also produced in the petroleum refining process.

Why is Vedantu’s Chapter 5 Coal and Petroleum Class 8 Notes Crucial?

There are many reasons why you should get chapter 5 coal and petroleum class 8 notes from Vedantu. And some of those reasons are:

• Each of the topics is explained by the experts in brief and in an easy language, making it easy for the students to understand the topics without getting help from friends, parents, or teachers.

• The notes help students quickly and effectively revise the entire chapter before the exam to feel confident and stress-free.

• The experts write the notes as per the latest CBSE syllabus issued by the board. 

• The notes help students to get clear and accurate information on all the topics covered in the chapter so that they last in students' memory for a longer duration.

• Class 8 Chapter 5 revision notes are free in downloadable pdf format. This helps the students to study at their own pace.

Important Questions For Practice

Very Short Answer Type Questions

1. Define petroleum.

2. How is bitumen, a petroleum product, used these days?

3. Are coal and petroleum fossil fuels?

4. Mention one benefit of CNG.

5. What does the term petrochemical mean?

Short Answer Type Questions

1. What are exhaustible and inexhaustible natural resources?

2. What are coal and coal tar?

3. Why is petroleum also known as black gold?

4. How are coal, petroleum, and natural gas prepared in the laboratory?

5. What does the term petrochemical mean?

Long Answer Type Questions

1. Mention one use of petrol, diesel, paraffin wax, lubricating oil, and petroleum gas in liquid form (LPG).

2. How to save petrol and diesel while driving?

3. How is petroleum formed?

4. Explain the process of refining petroleum.

Fill in the Blanks

1. The process of the gradual change of dead plant material into coal is called __________.

2. The slowest and the last stage of coal formation is known as __________.

3. The process of separation of crude oil into various components based on their boiling points is called __________.

4. The fraction of petroleum that is used as fuel for jet engines is called __________.

5. The process of breaking down large hydrocarbons into smaller hydrocarbons in the presence of heat and pressure is called __________.

True or False:

1. Coal is an inexhaustible natural resource.

2. Petroleum is a homogeneous mixture of various hydrocarbons.

3. The primary source of natural gas is volcanic eruptions.

4. Refining of petroleum is done by fractional distillation.

5. CNG stands for Compressed Natural Gas.

This was a complete discussion on the CBSE Class 8 Science Chapter 5 Coal And Petroleum revision note [Free PDF Download]. The revision notes offered here are intended to help students in memorizing the essential topics of the chapter Coal and Petroleum for a longer period. Download the pdf and start preparing the chapter to score good marks.

Conclusion

Diving into the world of coal and petroleum uncovers fascinating insights. Coal, born from ancient plants, fuels our energy needs, but its combustion affects the environment. Petroleum, a liquid treasure, powers vehicles and industries. However, we must conserve and wisely use these non-renewable resources to safeguard our planet's future. So, let's explore cleaner alternatives, reduce wastage, and embrace sustainable energy for a greener tomorrow. Remember, our choices today shape the world for generations to come. Coal and petroleum teach us not only about science but also about responsibility towards our Earth.