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SAI International School

Subject - Chemistry
Class - VIII

Topic – Coal and Petroleum

Sub-Topic – Petroleum

LESSON NOTE

Petroleum:

 The name ‘petroleum’ means rock oil. Petra means rock and Oleum means oil. It is called

petroleum because it is found under the crust of the earth trapped in rocks.
 Petroleum is a dark coloured, thick crude oil found deep below the ground trapped in the rocks.

 It is a complex mixture of hydrocarbons. It is insoluble in water.

How Petroleum was Formed?

 It was formed by the decomposition of the remains of tiny plants and animals buried under the
sea millions of years ago.

 Their bodies sank to the bottom of the sea and were soon covered by the mud and sand.
 Due to high pressure, heat and action of bacteria and in the absence of air, the dead remains

of plants and animals were slowly converted to petroleum and natural gas.

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