Coal & Petroleum Summary Class 8 NCERT Summary

Introduction

There are so many materials catering to our various needs on a daily basis. We drink water, eat food, breathe air, go to school, etc. All these things are available to us, but are all free of cost and readily accessible without fear of being depleted one day.

Not everything is readily available to us. For instance, sunlight, air, etc are resources which we find in abundance and it won’t be depleted any time soon. Hence, these resources are called Inexhaustible natural resources.Other resources are created in very limited quantities and it takes a very long time for such resources to be replenished. Such resources are known as exhaustible natural resources. Ex: coal, petroleum, minerals, natural gas, etc.Let us briefly understand a few of these exhaustible natural resources.

Coal and Petroleum

Coal and petroleum are formed as a result of degradation of ancient plant life which lived millions of years ago. These dead plant matter started to pile up, eventually forming a substance called peat. Over time, heat and pressure from geological processes transformed these materials into coal. Since these are formed from essentially fossils, they are also known as fossil fuels.

How Is Coal Formed?

Formation of coal dates back to millions of years ago, when the earth was covered only with vast moist forests, having huge trees, shrubs, ferns, etc. These plants underwent their life cycle and withered away, eventually falling back to the ground, most of which were swamps. New plants replaced them, they underwent a life cycle and the whole process continued repeatedly over the years, as a result of which the earth bed started accumulating all these dead plants.

Coal

This gave rise to a very thick layer of dead decomposed matter packing down plant matter washing away all the decayed matter. Physical and chemical changes took place as a result of heat and temperature extracting out all oxygen leaving the plant layers with carbon-rich content, thus resulting in the formation of coal over a period of time.

Types Of Coal

Coal is a readily combustible rock containing more than 50% by weight of carbon.

Coal formed can be of three types depending on the amount of oxygen, carbon and hydrogen they contain. They are:

Petroleum

Petroleum is a fossil fuel that naturally occurs in the liquid form created by the decomposition of organic matter beneath the surface of the earth millions of years ago. These fossil fuels are then refined into usable substances such as petrol, kerosene, etc. It is formed by the combination of hydrocarbons and other substances, mainly sulphur. When first collected in its natural form, it is termed as crude oil. This substance is generally characterized by a brownish-black colour. Although, it can also differ between red to pale yellow or even colourless. Its thickness (viscosity) varies from nearly solid tar-like consistency to low viscosity, almost like water.

Petroleum

Refining petroleum thus obtained yields many useful products. Let’s have a look at them.

Products of Petroleum

Petroleum products are obtained as a result of refining crude oil in oil refineries. There are numerous products that are created from petroleum and its by-products. A study reveals that by-products of petroleum alone provides scope to obtain 6000+ new products, to name a few, fertilizers, perfumes, flooring, insecticides, soaps, vitamins, petroleum jelly, etc.A few of the products obtained from petroleum are:

• Gasoline
• Diesel oil
• Kerosene
• Tar
• Heavy fuel oil
• Petroleum coke
• Lubricants
• Special Naphthas
• Paraffin wax
• Aviation Gasoline

Uses of Petroleum

Petroleum is one of the most important and widely used fuels in today’s time. Some of its advantages are:

• These are transportation fuels, i.e, via air, water or land.
• Diesel is used to power turbines for the production of electricity in large scale industries.
• Oil is used to produce electricity at homes and shops.
• Oils help lubricate different types of high-end machines used in different industries, hospitals, etc.
• Kerosene is used for domestic purposes at home.
• Used by chemical industries to produce plastic, dyes, paints, synthetic rubber, pesticides, perfumes, etc.

Natural Gas

• Natural gas is a crucial fossil fuel due to its ease of transport via pipelines.
• It is stored under high pressure as Compressed Natural Gas (CNG).
• CNG is used for power generation.
• CNG is a fuel for transport vehicles because it is less polluting.
• CNG is used for direct burning in homes and factories via pipeline networks (e.g., in Vadodara, Delhi).
• Natural gas is a starting material for manufacturing various chemicals and fertilizers.
• In India, natural gas is found in Tripura, Rajasthan, Maharashtra, and the Krishna Godavari delta.
• Natural gas is considered a cleaner fuel compared to other fossil fuels.
• Petrochemicals derived from natural gas are used to produce detergents, fibers, plastics, and other materials.
• Natural gas is formed from dead sea organisms that settled at the bottom of the sea and were transformed over millions of years under high temperature and pressure conditions.

LPG

Key Points

• Inexhaustible natural resources like sunlight and air are abundant and won't deplete soon.
• Exhaustible natural resources like coal and petroleum are limited and take a long time to replenish.
• Coal and petroleum are formed from the degradation of ancient plant life millions of years ago.
• Coal forms from plant matter accumulating in swamps, undergoing physical and chemical changes over time.
• Types of coal include lignite, bituminous, and anthracite, varying by carbon content.
• Petroleum is a liquid fossil fuel formed from decomposed organic matter beneath the Earth's surface.
• Crude oil is the natural form of petroleum, varying in color and viscosity.
• Refining petroleum produces many useful products such as petrol, kerosene, and diesel oil.
• By-products of petroleum can produce over 6000 new products, including fertilizers, perfumes, and soaps.
• Gasoline, diesel oil, kerosene, and tar are some products obtained from refining petroleum.
• Petroleum coke, lubricants, and paraffin wax are other products derived from petroleum.
• Aviation gasoline is a specialized fuel obtained from petroleum refining.
• Petroleum is crucial for transportation, powering turbines, and producing electricity.
• Oils from petroleum are used to lubricate high-end machines in various industries.
• Chemical industries use petroleum to produce plastic, dyes, paints, synthetic rubber, and more.