What are petrochemicals ? What are their uses ?
Substance which are obtained from petroleum and natural gas are called petrochemicals .
Petrochemical are used in the manfacture of detergent, fibres, polythene and other plastics and fertilizers.
Why is coke considered a better fuel than coal ? Give four reasons.
(i) Coke burns without producing smoke whereas coal produces a lot of smoke on burning
(ii) Coke has a higher calorific value than coal.
(iii) Coke burns more readily than coal.
(iv) Coke leaves much less ash in burning as compared to coal.
State two precautions that should be taken in using fossil fuels to avert the energy crises ?
(i) Fossil fuels should be used only when no alternative source of energy is available.
(ii) Wastage of fossil fuels should be prevented in homes, transport and industry. Switch off the engine at traffic lights or at a place where you have to wait,Ensure correct tyre pressure, and Ensure regular maintenance of the vehicle.
What are the consequences of the green house effect ?
Due to the green house effect, temperature on the earth will rise and the polar ice will melt. This will cause flooding of low lying areas. The rise in temperature on the earth, will affect monsoon and pattern of crop cultivation.
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