8th Class Science: Coal and Petroleum

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Questions and Answers

What is the process of conversion of dead vegetation into coal called?

carbonisation

What are the characteristics of coke?

Coke is a tough, porous, and black substance, and is an almost pure form of carbon.

What are natural resources?

Substances present on the earth that allow the existence of life and satisfy the needs of living organisms.

What is the difference between exhaustible and inexhaustible natural resources?

Exhaustible natural resources are present in limited quantity and can be depleted, whereas inexhaustible natural resources are present in unlimited quantity and are not likely to be exhausted. Signup and view all the answers

How was coal formed?

Coal was formed from the burial of dense forests in low-lying wetland areas, followed by compression and increased temperature. Signup and view all the answers

What is the significance of coke in the extraction of metals?

Coke is used as a fuel in the extraction of many metals. Signup and view all the answers

What is the role of coke in the manufacture of steel?

Coke is used in the manufacture of steel. Signup and view all the answers

Give an example of an inexhaustible natural resource.

Sunlight Signup and view all the answers

What is the main reason why fossil fuels are considered exhaustible natural resources?

Fossil fuels require millions of years to form from the dead remains of plants and animals, and the amount of this source in nature is limited. Signup and view all the answers

What are the advantages of using CNG and LPG as fuels?

They can be burnt directly, easily transported through pipelines, have higher calorific value, and are cleaner fuels that burn without smoke. Signup and view all the answers

What are the characteristics of coal tar?

Coal tar is a thick black liquid with an unpleasant smell, and it is a mixture of about 200 carbon compounds. Signup and view all the answers

How is petroleum formed?

Petroleum is formed from dead organisms living in the sea, which are converted into petroleum and natural gas over millions of years under high pressure and temperature. Signup and view all the answers

What is the process of refining of petroleum?

The process of separating the various constituents or fractions of petroleum is known as refining of petroleum. Signup and view all the answers

What is a characteristic of natural gas?

Natural gas always gets collected above petroleum under high pressure. Signup and view all the answers

What is the role of high temperature and pressure in the formation of coal?

High temperature and pressure are necessary for the conversion of dead plants into coal. Signup and view all the answers

What is one of the uses of coal tar?

Coal tar is used to make naphthalene balls. Signup and view all the answers

Study Notes

Carbonisation and Coal

Carbonisation is the slow process of converting dead vegetation into coal, which mainly contains carbon.
Coke is a tough, porous, and black substance that is an almost pure form of carbon.
Uses of coke: manufacturing steel, extracting metals, and as a fuel.

Natural Resources

Natural resources are substances present on the earth that allow the existence of life and satisfy the needs of living organisms.
Inexhaustible natural resources: unlimited quantity, not likely to be exhausted by human activities (e.g., sunlight, air, and water).
Exhaustible natural resources: limited quantity, likely to be exhausted by human activities (e.g., forests, wildlife, minerals, coal, petroleum, and natural gas).

Formation of Coal

Coal was formed around 300 million years ago from dense forests in low-lying wetland areas.
Natural processes like flooding buried these forests under soil, compressing them, and increasing temperature.
Under high temperature and pressure, dead plants converted into coal.

Fossil Fuels

Fossil fuels require millions of years to form from dead plants and animals.
Amount of fossil fuels in nature is limited, making them exhaustible resources.

Advantages of CNG and LPG

CNG and LPG can be burnt directly and easily transported through pipelines.
They have higher calorific value than other fuels and are cleaner fuel, burning without smoke.

Coal Tar

Coal tar is a thick, black liquid with an unpleasant smell and a mixture of about 200 carbon compounds.
Uses of coal tar: making synthetic dyes, drugs, explosives, perfumes, plastics, paints, and roofing materials.

Formation of Petroleum

Petroleum was formed from organisms living in the sea, which settled at the bottom and got covered with layers of sand and clay.
Over millions of years, dead organisms converted into petroleum and natural gas under high pressure and temperature.
Petroleum and natural gas get trapped between two layers of rocks, with natural gas collecting above petroleum under high pressure.