1. Write down any four amorphous forms of carbon.
Ans. Amorphous forms of carbon – coal, charcoal, coke and lamp black.

2. Explain the process of formation of petroleum
Ans. Petroleum is formed by the decomposition of aquatic plants and animal remains.

3. Give a few examples of  inexhaustible and exhaustible natural resources.
Ans. Exhaustible resources – forests, wildlife, coal

     Inexhaustible resources – air, sunlight, water.

4. Why are coal and petroleum known as fossil fuels
Ans: Coal and petroleum are formed from the dead remains of living organisms that is why they are called fossils fuels.

5. What is meant by refining of petroleum and where is it done
Ans. The process of separating the different fractions of petroleum is known as refining and it is carried out in a refinery.

6. Give two uses of diesel.
Ans. i) Diesel is used as fuel for heavy motor vehicles.

ii) It is used in electric generators.

7. How can petrol be used
Ans. Petrol can be used as a motor fuel, aviation fuel and as solvent for dry cleaning.

8. How can bitumen be used.
Ans. Bitumen can be used for making paints and for surfacing the roads.

9. Why is petroleum also known as ‘black gold’
Ans. The fuels like petroleum gas, petrol, diesel, kerosene, lubricating oils, paraffin wax. etc. are obtained from petroleum. Also the petrochemicals derived from petroleum are used in the manufacture of some important substances like synthetic fibres, detergents, polythene, man-made plastics etc. Due to its great commercial importance, petroleum is known as ‘black gold’.

10. Can we make coal and petroleum in the laboratory from dead organisms.
Ans. No, their formation is a very slow process and conditions for their formation cannot be reached in the laboratory.

11. Give two disadvantages of using fossil fuels.
Ans. Fossil fuels cause air pollution and global warming.

12. Why should the fossil fuels be used with care
Ans. If we use fossil fuels carefully, it will result in a better environment, less risk of global warming and they will be available for a longer period.

13. Name some places in India where natural gas has been found.
Ans. In India natural gas is found in Tripura, Jaisalmer and in the offshore of Mumbai and in Krishna Godavari delta.

14. Define the term fossil fuel. Name two fossil fuels.
Ans. Fossil fuels are formed from dead remains of living matter over millions of years when they remained buried under the earth. Coal and petroleum are two such fossil fuels.

15. State one use of each of the following: Charcoal, Bone Charcoal, Coke.
i) Charcoal: It is used as a Fuel.
ii) Bone Charcoal: It is used in the purification of brown coloured sugarcane juice in the manufacture of sugar.
iii) Coke: It is used as a reducing agent in the extraction of metals.

16. Name the products obtained when coal is heated in the absence of air.
Ans. Coke is formed when coal is heated in the absence of air.

17. (a) Give the full form of            (i) LPG                 (ii) CNG.

(b) How is petroleum gas obtained.
(a) (i) LPG —  Liquefied Petroleum Gas.
(ii) CNG — Compressed Natural Gas.
(b) Petroleum gas is obtained during fractional distillation of petroleum.

18. What are ‘Petrochemicals’ Give the uses of petrochemicals obtained from petroleum.
Ans. Petrochemicals are useful substances obtained from petroleum. They are used in the manufacture of detergents, fibres, polyethylene and other plastics.

19. Describe characteristics of coke.
Ans. Characteristics of coke are it is tough, it is porous and it is a pure form of carbon.