Class 8th Chemistry // Short Questions & Answer // Coal and Petroleum // English Medium

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Question 1. Name the petroleum product used for surfacing roads.
Answer: A petroleum product ‘Bitumen’ is used for surfacing of roads.

Question 2: Name the petroleum product used for surfacing of roads.
Answer: Bitumen

Question 3. What is the slow process of conversion of dead vegetation into coal called ?
Answer: Carbonisation.

Question 4. What are natural resources ?
Answer: Material obtained from nature are called natural resources.

Question 5. Classify the following as exhaustible and inexhaustible natural resources- air, sunlight, water, forests, wildlife, coal.
Answer: Exhaustible resources – forests, wildlife, coal
Inexhaustible resources – air, sunlight, water.

Question 6. Define carbonisation.
Answer: The slow process of conversion of dead vegetation into coal is called carbonisation.

Question 7. What name is given to the process of heating a substance in absence of air ?
Answer: Destructive Distillation.

Question 8. How is coke obtained ?
Answer: Coke is obtained by heating coal in the absence of air.

Question 9. How is coal tar formed ?
Answer: When destructive distillation of coal is done, the vapours which condense in the water form coal tar.

Question 10. Why is petroleum called a fossil fuel ?
Answer: Petroleum is called a fossil fuel as it is obtained from the bodies of dead organisms.

Question 11. How is natural gas formed ?
Answer: Natural gas is formed below the earth’s surface. It is formed above the petroleum.

Question 12. Write down any four amorphous forms of carbon. 
Answer: Amorphous forms of carbon – coal, charcoal, coke and lamp black.

Question 13. Explain the process of formation of petroleum ? Name two places in India where it is found.
Answer: Petroleum is formed by the decomposition of aquatic plants and animal remains. In India, petroleum is obtained from oil wells in Assam and Bombay .

Question 14. Distinguish between inexhaustible and exhaustible natural resources.
Answer: Exhaustible resources – forests, wildlife, coal
Inexhaustible resources – air, sunlight, water.

Question 15. Why are coal and petroleum known as fossil fuels ?
Answer: Coal and petroleum are formed from the dead remains of living organisms that is why they are called fossils fuels.

Question 16. What is meant by refining of petroleum and where is it done ?
Answer: The process of separating the different fractions of petroleum is known as refining and it is carried out in a refinery.

Question 17. Give two uses of diesel.
Answer: Diesel is used as fuel for heavy motor vehicles and in electric generators.

Question 18. How can petrol be used ?
Answer: Petrol can be used as a motor fuel, aviation fuel and as solvent for dry cleaning.

Question 19. How can bitumen be used ?
Answer: Bitumen can be used for making paints and for surfacing the roads.

Question 20. Why is petroleum also knbwn as ‘black gold’ ?
Answer: Due to its great commercial importance, petroleum is known as ‘black gold’.

Question 21. Can we make coal and petroleum in the laboratory from dead organisms ?
Answer: No, their formation is a very slow process and conditions for their formation cannot be reached in the laboratory.

Question 22. Give two disadvantages of using fossil fuels.
Answer: Fossil fuels cause air pollution and global warming.

Question 23. Why should the fossil fuels be used with care ?
Answer: If we use fossil fuels carefully, it will result in better environment, less risk of global warming and they will be available for a longer period.

Question 24. What is meant by fractional distillation ? What is the principle on which it is based ?
Answer: Petroleum is mixture of various hydrocarbons having different boiling points. As the number of carbon atoms increase, the boiling point also increases. This property is used to separate the different components of petroleum and is known as fractional distillation.

Question 25. Name some places in India where natural gas has been found.
Answer: In India natural gas is found in Tripura, Jaisalmer and in the offshore of Mumbai and in Krishna Godavari delta.

Question 26. Give two advantages of judicious use of energy ?
Answer: The advantages of judicious use of energy are :

• It will delay the energy crisis.
• It will give the scientists more time to develop more efficient alternate sources of energy.
  

  
  Question 27. Define the term fossil fuel. Name two fossil fuels.
  Answer: 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 fossil fuels.

  Question 28. State one use of each of the following : 

  • Charcoal
  • Bone Charcoal
  • Coke.

  Answer:
  Use:

  • Charcoal : Fuel.
  • Bone Charcoal : Purification of brown coloured sugarcane juice in the manufacture of sugar.
  • Coke : Used as a reducing agent in the extraction of metals.

  Question 29.

  1. Name the products obtained when coal is heated in the absence of air.
  2. Write any two uses of its products. 

  Answer:

  1. Coke is formed when coal is heated in absence of air.
  2. Coke is used :
     • As a fuel.
     • As a reducing agent in the extraction of metals.

  Question 30. (a) Give the full form of
  (i) LPG
  (ii) CNG.
  (b) How is petroleum gas obtained ?
  Answer:
  (a) (i) LPG — Liquefied Petroleum Gas.
  (ii) CNG — Compressed Natural Gas.
  (b) Petroleum gas is obtained during fractional distillation of petroleum.

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