Coal and Petroleum class 8 notes: Class 8 science ch 3 notes
| Textbook | Ncert |
| Class | Class 8 |
| Subject | Science |
| Chapter | Chapter 3 |
| Chapter Name | Coal and Petroleum |
| Medium | English |
Are you looking for Class 8 Science chapter 3 notes? Now you can download Coal and Petroleum class 8 notes pdf from here. In this chapter, we learn about natural resources like coal, petroleum, and natural gas, which are fossil fuels. The chapter also explains how petroleum refining is done and highlights the importance of natural gas as a clean fuel. It discusses the need for conservation of fossil fuels and introduces the concept of Petrochemicals and CNG (Compressed Natural Gas) as alternatives.
🌍 Resources :-
Nature provides us with everything necessary for a comfortable and sustainable life. It offers us air to breathe, water to drink, food to eat, sunlight for energy, and minerals for various uses. These essential elements are called resources. Resources can be classified into natural and man-made categories.
🌱 Natural Resources :-
The resources, that are obtained from nature are called natural resources, for example, air, water, soil and minerals.
🔍 Types of Natural Resources :-
Natural resources can be broadly classified into two kinds:
♾️ (i) Inexhaustible Natural Resources: These resources are present in unlimited quantity in nature and are not likely to be exhausted by human activities. Examples are: sunlight, air.
⚠️ (ii) Exhaustible Natural Resources: The amount of these resources in nature is limited. They can be exhausted by human activities. Examples of these resources are forests, wildlife, minerals, coal, petroleum, natural gas etc.
🔥 Fossil fuels :-
Fossil fuels were formed from the dead remains of living organisms millions of years ago. Coal, petroleum and natural gas are fossil fuels. Fossil fuels are exhaustible resources.
🪨 Coal :-
Coal is a hard, black-colored natural fuel formed from the remains of ancient plants. It is used as a source of energy for cooking, generating electricity, and powering industrial processes.
📖 Formation of Coal ( Story of Coal ) :-
There were dense forests in low lying areas on earth; about 300 million years ago. Those forests got buried under the soil Due to natural processes, like flooding. More layers of soil were deposited on these buried forests in due course of time. Those plants were converted into coal due to intense pressure and heat inside the earth.
🧪 Carbonisation :-
The process of converting dead vegetation into coal is called carbonisation..
🔧 Uses of coal :-
- Coal burns in air to produce heat and carbon dioxide. Coal is used as fuel because it provides high amount of heat.
- Coal was used as fuel in steam engines.
- Most of the thermal power plants still use coal as fuel.
- Coal is still being used as kitchen fuel in some households, dhabas and restaurants.
- Many useful products; like coke, coal tar and coal gas; are made by processing coal.
🏭 Product of obtaines from Coal :-
Coal is processed in industry to get some useful products such as coke, coal tar and coal gas.
🧱 Coke :- Coke is almost pure form of carbon, It is a tough, porous ous and black substance. Coke is used in the manufacture of steel and in the extraction of many metals.
🛢️ Coal Tar :- It is a black, thick liquid with an unpleasant smell. sm It is a mixture of about 200 substances. Products Sub obtained from coal tar are used as starting materials for manufacturing various substances used in everyday life and in industry, like synthetic dyes, drugs, explosives, perfumes, plastics, paints, photographic materials, roofing materials, etc.
💨 Coal Gas :- Coal gas is produced during processing of coke from coal. Coal gas is used as fuel in many industries which are situated near coal mines.
⛽ Petroleum :-
The natural resource from which petrol and diesel are obtained is called petroleum.
Meaning of Petroleum: The word petroleum is derived from: Petra = rock, Oleum = oil. It is called petroleum because it is extracted from layers of rock beneath the Earth’s surface
🚗 Use of Petrol and Diesel :-
- Petrol is used as a fuel in light vehicles such as motorcycles, scooters, and cars.
- Diesel is used in heavy motor vehicles like trucks, buses, and tractors.
🌊 Formation of Petroleum :-
Petroleum was formed from organisms living in the sea. As these organisms died, their bodies settled at the bottom of the sea and got covered with layers of sand and clay. Over millions of years, absence of air, high temperature and high pressure transformed the dead organisms into petroleum and natural gas.
🏗️ Petroleum and Its Refining :-
- Nature of Petroleum: Petroleum is a dark, oily liquid with an unpleasant odour. It is a mixture of various constituents.
- Major Constituents of Petroleum: Petroleum gas, Petrol, Diesel, Lubricating oil, Paraffin wax, And other useful substances
- Refining of Petroleum: The process of separating the various constituents or fractions of petroleum is called refining. Refining is done in a petroleum refinery.
🧪 Petrochemicals :-
Many useful substances are obtained from petroleum and natural gas. These substances are collectively known as petrochemicals. These are used in the manufacture of detergents, fibres (polyester, nylon, acrylic etc.), polythene and other man-made plastics.
💨 Natural Gas :-
Natural gas is a fossil fuel found deep beneath the Earth’s surface, often alongside petroleum deposits. It is a clean, colourless, and odourless gas, mainly composed of methane. Natural gas is used as a fuel for cooking, heating, and generating electricity, and also as a raw material in the chemical industry. In our country. natural gas has been found in Tripura. Rajasthan, Maharashtra and in the Krishna Godavari delta.
🚙 Compressed Natural Gas (CNG) :-
CNG is compressed natural gas. Natural gas is a very important fossil fuel because it is easy to transport through pipes. Natural gas is stored under high pressure as compressed natural gas (CNG).
Used of CNG :- CNG is used for power generation. It is now being used as a fuel for transport vehicles because it is less polluting. It is a cleaner fuel.
✅ Advantages of CNG (Compressed Natural Gas) :-
- Eco-friendly – Produces less air pollution compared to petrol and diesel
- Cheaper – More cost-effective than other fuels
- Efficient – Burns cleanly and completely
- Safe – Lighter than air; disperses easily in case of leaks
- Less engine wear – Causes less damage to engine parts
⚠️ Drawbacks of Fossil Fuels :-
- Non-renewable: Fossil fuels are exhaustible resources and may get depleted in the near future if not used wisely.
- Environmental Pollution: Burning fossil fuels releases carbon dioxide (CO₂) and other harmful gases, leading to air pollution.
- Global Warming: The excess CO₂ from fossil fuels traps heat in the atmosphere, contributing to global warming and climate change.
PCRA recommendations for conservation of petrol and diesel:
In India, the Petroleum Conservation Research Association (PCRA) advises people how to save petrol/diesel while driving. Their tips are:
- Drive at constant and moderate speed as far as possible,
- Switch off the engine at traffic lights or at a place where you have to wait,
- Ensure correct tyre pressure, and
- Ensure regular maintenance of the vehicle.