scientific reasons[2 marks ]

Question 12 Marks

Can forests help reduce the pollution caused by burning of fossil fuels? How?

Answer

Not all, but yes it reduces some of the pollution like carbon dioxide emitted during burning of fossil fuels.

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Question 22 Marks

None of the fuels is clean fuel. Comment.

Answer

On burning, every fuel releases atleast $CO_2$ which causes greenhouse effect. Thus none of the fuels are clean.

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Question 32 Marks

You are provided with a mixture of petroleum and water. How will you separate the two?

Answer

Allow to stand the mixture of petroleum and water undisturbed for some time. The top layer will be consisted of petroleum which can be separated from water by decantation.

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Question 42 Marks

Petroleum is called ‘black gold’.

Answer

$-$Many useful substances are obtained from petroleum.
$-$These are used in the manufacture of detergents, fibres, lubricatings, colours.
$-$Due to its great commercial importance, Petroleum, the black liquid, is called ‘black Bold’.

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Question 52 Marks

Fossil fuels are exhaustible natural resources.

Answer

$-$Fossil fuels were formed from the dead remains of living organisms.
$-$required millions of years for the conversion of dead organisms into these fuels.
$-$Fossil fuels stocks are limited.
$-$So fossil fuels are exhaustible natural resources.

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Science scientific reasons[2 marks ]

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