COAL AND PETROLEUM | Class 8 Science Notes
By ConceptScroll Team · Published on 17 July 2026 · 3 min read
COAL AND PETROLEUM – this guide gives you a concise, exam-ready overview of COAL AND PETROLEUM from Class 8 Science, written by ConceptScroll editors and reviewed against the latest NCERT textbook.
Petroleum
Petroleum, also known as crude oil, is a dark, oily liquid fossil fuel formed from the remains of tiny plants and animals that lived in ancient seas millions of years ago. When these organisms died, their bodies settled at the bottom of the sea and were covered by layers of sand and clay. Over millions of years, the absence of air, combined with high temperature and pressure, transformed these remains into petroleum and natural gas.
Petroleum is found trapped in underground reservoirs, usually above water layers, because oil and gas are lighter than water and do not mix with it. The world's first oil well was drilled in Pennsylvania, USA, in 1859. In India, petroleum is found in Assam, Gujarat, Mumbai High, and the river basins of Godavari and Krishna.
Petroleum is a mixture of various hydrocarbons and other compounds such as petroleum gas, petrol, diesel, lubricating oil, paraffin wax, and bitumen. To make these usable, petroleum undergoes refining in petroleum refineries where it is separated into different fractions based on boiling points through a process called fractional distillation.
Petroleum products are widely used in daily life and industries. Petrol and diesel are primary fuels for vehicles, kerosene is used for cooking and lighting, lubricating oils reduce friction in machines, paraffin wax is used in candles and ointments, and bitumen is used for road surfacing and roofing.
Petrochemicals derived from petroleum and natural gas are raw materials for manufacturing detergents, synthetic fibers like polyester and nylon, plastics, and fertilizers. Hydrogen obtained from natural gas is used to produce urea fertilizer. Due to its immense commercial value, petroleum is often called 'black gold.'
📊 Diagram: Fig. 3.4 : Petroleum and natural gas deposits; Fig. 3.5: A petroleum refinery (See figure_6, figure_7)
🔗 Connection: Introduces natural gas, another fossil fuel associated with petroleum.
Frequently asked questions
1. What are the advantages of using CNG and LPG as fuels?
Advantages of using CNG and LPG as fuels include:
- They are cleaner fuels compared to petrol and diesel, producing fewer pollutants and less smoke.
- They burn more efficiently, providing better mileage.
- They reduce air pollution and are better for the environment.
- They are safer to handle and store compared to petrol and diesel.
- They are economical and cost-effective in the long run.
2. Name the petroleum product used for surfacing of roads.
The petroleum product used for surfacing of roads is bitumen.
3. Describe how coal is formed from dead vegetation. What is this process called?
Coal is formed from dead vegetation through a process called carbonization. When plants die, they accumulate in swampy areas and get buried under layers of soil and sediments. Over millions of years, due to high pressure and temperature, the dead plant material undergoes physical and chemical changes, losing moisture and volatile substances, and gradually transforms into coal.
4. Fill in the blanks. (a) Fossil fuels are __________, __________ and __________. (b) Process of separation of different constituents from petroleum is called __________. (c) Least polluting fuel for vehicle is __________.
(a) Fossil fuels are coal, petroleum and natural gas. (b) Process of separation of different constituents from petroleum is called fractional distillation. (c) Least polluting fuel for vehicle is CNG.
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