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We say fossil fuels will last only for a few hundred years. Comment.

Fossils fuels take millions of years to get converted into these fuels. Formation of fossil fuels requires specific conditions and it doesn’t happen quite often. Therefore, their limited stock will last only for a few hundred years.

ScienceClass 8CBSE

Name the products obtained and their uses when coal is processed in industry.

Coke, coal tar and coal gas are obtained when we process coal. Coke is used as reducing agent in the extraction of metals. Coal tar is used as starting material for manufacturing various sustances such as synthetic dyes, drugs, explosives, perfumes, paints etc. Coal gas is used as fuel.

ScienceClass 8CBSE

Match the items given in Column I with the items of Column II. Column I Column II (a) Used for road surfacing (i) Black gold (b) Natural gas (ii) Vaseline and candles (c) Petroleum (iii) Bitumen Paraffin wax (iv) CNG

Soln: Column I Column II Used for road surfacing (iii) Bitumen Natural gas (iv) CNG Petroleum (i) Black gold Paraffin wax (ii) Vaseline and candles

ScienceClass 8CBSE

Fill in the blanks and complete the story. About 300 million years ago the earth had dense in low lying wetland areas. Due to natural processes, like , these forests got burried under the . As more deposited over them, they were compressed. The also rose as they sank deeper and deeper. Under high and high , dead plants got slowly converted into coal.

About 300 million years ago the earth had dense forestsin low lying wetland areas. Due to natural processes, like floods, these forests got burried under the soil. As more soil deposited over them, they were compressed. The temperaturealso rose as they sank deeper and deeper. Under high temperature and high temperature, dead plants got slowly converted into coal

ScienceClass 8CBSE

Write the characteristics and some important uses of coal.

Characteristics of coal. It is as hard as stone and is black in It is Combustible It is a fossil fuel When it is burned in air it releases CO Uses of Coal Coal is one of the fuels used to cook Earlier, it was used in railway engines to produce steam to run the It is also used in thermal power plants to produce Coal is also used as a fuel in various

ScienceClass 8CBSE

Write two important uses of coke.

Important uses of coke are as follows Coke is used as reducing agent in extraction of metal from its Coke is used in the manufacture of steel

ScienceClass 8CBSE

Sunlight and air are inexhaustible natural resources. Comment.

Soln: Sunlight is present in unlimited and they will not get exhausted by any means. Hence Sunlight is inexhaustible natural resources. Some natural resources are given in a Classify them into the exhaustible and inexhaustible natural resources. air, coal, natural gas, sunlight, petroleum, minerals, forests, oxygen. Soln: Exhaustible Inexhaustible coal air natural gas sunlight, petroleum, oxygen. minerals Forests

ScienceClass 8CBSE

Write True/False against the following statements. (a) Oxygen in air is an exhaustible natural resource. (b) Resources which are present in unlimited quantity in nature are called exhaustible natural resources. (c) Wildlife is an exhaustible natural resource. (d) Under high temperature and pressure, dead plants get slowly converted to coal. (e) CNG is less polluting fuel than petrol and diesel.

False Explanation: Oxygen is not an exhaustible natural resource. False, Explanation: Resources which are present in unlimited quantity in nature are called inexhaustible natural resources. True, True,

ScienceClass 8CBSE

Fill in the blanks. (a) The slow process of conversion of dead vegetation into coal is called . (b) Coal and petroleum are formed from the dead remains of organisms and are known as . (c) The black thick liquid with smell is known as coal tar. (d) During the processing of coal to get coke, coal tar and are also obtained. (e) The process of separating the various constituents of petroleum is known as . (f) Excessive burning of fossil fuels is a major cause of .

The slow process of conversion of dead vegetation into coal is called carbonisation. Coal and petroleum are formed from the dead remains of organisms and are known as fossil fuels. The black thick liquid with unpleasantsmell is known as coal During the processing of coal to get coke, coal tar and coal gasare also The process of separating the various constituents of petroleum is known as refining. Excessive burning of fossil fuels is a major cause of air pollution.

ScienceClass 8CBSE

1. The underlined words in the following sentences have been jumbled up. Write them in their correct form. (a) Loca is obtained from mines. (b) Umpetlore is a fossil fuel. (c) Rineryfe is a place where various fractions of peroleum are separated. (d) Keenrose is a fuel used in jet crafts. (e) Nutsgilh is an example of inexhaustible natural resources.

coal petroleum refinery kerosene sunlight

ScienceClass 8CBSE

Fill in the blanks in the following sentences. (a) Coal is one of the used to cook food. (b) When heated in air, coal burns and produces mainly gas. (c) Coal tar is a black, thick with an smell. (d) Petroleum, and are fossil fuels. (e) Forests and coal are natural resources.

Coal is one of the fuel used to cook When heated in air, coal burns and produces mainly Carbon-di-oxide Coal tar is a black, thick liquid with an unpleasant Petroleum, Coal and natural gas are fossil Forests and coal are exhaustible natural

ScienceClass 8CBSE

Name the petroleum product used as fuel for stoves, lamps and jet aircrafts.

Kerosene is the petroleum product used as fuel for stoves, lamps and jet aircrafts.

ScienceClass 8CBSE

What does CNG stand for and why is it considered to be a better fuel than petrol?

CNG stands for compressed natural gas. CNG burns with no smoke hence it does not cause air pollution. CNG does not produce any poisonous gas hence CNG is considered a better fuel than petrol.

ScienceClass 8CBSE

You are provided with a mixture of petroleum and water. Can you suggest a method to separate the two?

Decantation method is used to separate mixture of petroleum and water.

ScienceClass 8CBSE

Choose the incorrect statement from the following: (a) It is difficult to transport natural gas through pipes. (b) The disadvantage of natural gas is that it can not be used directly for burning in homes. (c) Natural gas is stored under high pressure as compressed natural gas. (d) Natural gas cannot be used for power generation.

Soln: Answer is (d) Natural gas cannot be used for power generation. Explanation: Natural gas can be used for power generation hence statement d) is wrong

ScienceClass 8CBSE

Petroleum was formed from organisms: (a) living on the land (b) living on the plants (c) living in the sea living on the rocks

Soln: Answer is (c) living in the sea Explanation: 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, absence of air, high temperature and high pressure transformed the dead organisms into petroleum and natural gas.

ScienceClass 8CBSE

Which of the following is not a constituent of petroleum? (a) paraffin wax (b) lubricating oil (c) petrol coke

Soln: Answer is (b) lubricating oil Explanation: Lubricating oil is obtained from crude petroleum.

ScienceClass 8CBSE

Naphthalene balls are obtained from coal tar and are used as (a) mosquito repellant (b) honey bee repellant (c) moth repellant snake repellant

Answer is (c) moth repellant Explanation: Characteristic smell of naphthalene makes the insects and moth run away from naphthalene stored under clothes etc.

ScienceClass 8CBSE

Coal is formed from the remains of (a) vegetation only (b) animals only (c) both vegetation and animals neither vegetation nor animals

Answer is (d) neither vegetation nor animals Explanation: Coal is formed 300 million years ago when buried plants and trees get decomposed.

ScienceClass 8CBSE

Which substance is formed by the carbonisation of dead vegetation?. (a) coal (b) coke (c) coal gas coal tar

Ansswer is (a) coal Explanation: Coal is formed 300 million years ago when buried plants and trees get decomposed.

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