Class 8 Science Chapter 5 Notes Pdf Coal And Petroleum Notes
In this post, we will discuss Class 8 Science Chapter 5 notes pdf Coal And Petroleum. Class 8th science ch 5 notes help students in revision. In Coal And Petroleum notes class 8, we will learn about natural resources, Classification of Natural Resources. You can also download Coal And Petroleum note class 8 pdf for further study. NCERT notes for Class 8 Science Chapter 5 are designed by our subject expert team.
In this Class 8th Science Ch 5 Notes pdf, we will learn about Coal And Petroleum Notes.
Class 8 Science Chapter 5 notes Overview
We use various materials for our basic needs. Some of them are found in nature and some have been made by human efforts.
Natural Resources:-The resources, that are obtained from nature are called natural resources. Example air, water, soil etc.
Classification of Natural Resources
- Inexhaustible Natural Resources
- Exhaustible Natural Resources
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 and air.
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:- some exhaustible natural resources like coal, petroleum and natural gas. These were formed from the dead remains of living organisms (fossils). So, these are all known as fossil fuels. example coal, petroleum and gas.
- Coal is a fossil fuel, that was formed by the decay of vegetation(nature), which existed a million years ago.
- Coal is a non-crystalline form of carbon.
- Coal is as hard as stone and is black in colour.
- Coal is one of the fuels used to cook food.
- Earlier, it was used in railway engines to produce steam to run the engine.
- It is also used in thermal power plants to produce electricity.
- Coal is also used as a fuel in various industries.
- Coal is processed in the industry to get some useful products such as coke, coal tar and coal gas.
Carbonisation:- The slow process of conversion of dead vegetation into coal is called carbonisation.
- It is a tough, porous and black substance.
- It is an almost pure and amorphous form of carbon.
- It is harder and denser than charcoal.
- It is obtained by heating soft coal in the absence or little supply of air.
- Coke is used in the manufacture of steel and in the extraction of many metals.
- Coal Tar is a black, thick liquid with an unpleasant smell.
- It is a mixture of about 200 substances.
- coal tar is 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.
- These days, bitumen, a petroleum product, is used in place of coal tar for metalling the roads.
- Coal gas is obtained during the processing of coal to get a coke.
- It is used as fuel.
As you know that petrol is used as a fuel in light automobiles such as motorcycles/ scooters and cars. Heavy motor vehicles like trucks and tractors run on diesel. Petrol and diesel are obtained from a natural resource called petroleum.
- The word petroleum is derived from petra (rock) and oleum (oil) as it is mined from between the rocks under Earth.
- 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, the absence of air, high temperature and high pressure transformed the dead organisms into petroleum and natural gas.
- Petroleum is a dark oily liquid.
- It has an unpleasant odour.
Refining of Petroleum
It is a mixture of various constituents such as petroleum gas, petrol, diesel, lubricating oil, paraffin wax, etc. The process of separating the various constituents/ fractions of petroleum is known as refining. It is carried out in a petroleum refinery.
|Constituents of Petroleum
|Petroleum Gas in Liquid form(LPG)
|Fuel for home and industry
|Motor fuel, aviation fuel, solvent for dry cleaning
|Fuel for stoves, lamps and for jet aircraft
|Fuel for heavy motor vehicles, electric
|Ointments, candles, vaseline etc.
|Paints, road surfacing
- 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).
- CNG is used for power generation.
- CNG is used as a fuel for transport vehicles because it is less polluting. It is a cleaner fuel.
- Natural gas is also used as a starting material for the manufacture of a number of chemicals and fertilisers.
- CNG is used directly for burning in homes and factories where it can be supplied through pipes.
Some Natural Resources are Limited
Coal and petroleum are fossil fuels. It required the dead organisms for millions of years to get converted into these fuels.
The burning of these fuels is a major cause of air pollution. Their use is also linked to global warming. It is, therefore, necessary that we use these fuels only when absolutely necessary. This will result in a better environment, a smaller risk of global warming and their availability for a longer period of time.
What We Learn Coal And Petroleum Notes
In Class 8th Science Ch 5 Notes pdf / Coal And Petroleum Notes
- Coal, petroleum and natural gas are fossil fuels.
- Fossil fuels were formed from the dead remains of living organisms millions of years ago.
- Fossil fuels are exhaustible resources.
- Coke, coal tar and coal gas are the products of coal.
- Petroleum gas, petrol, diesel, kerosene, paraffin wax, and lubricating oil are obtained by refining petroleum.
- Coal and petroleum resources are limited. We should use them judiciously.
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