Chapter 5: Coal and Petroleum (Solutions)
Posted on : 19-11-2017 Posted by : Admin

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INTEXT QUESTIONS

1. Make a list of various materials used by us in daily life and classify them as natural and man-made.

2. Can we use all our natural resources forever?

Answer: We cannot use all our natural resources forever. The natural resources like sunlight, wind can be used forever, however the resources like Coal, petroleum, natural gas, water cannot be used forever as their amount is only limited.

3. Where do we get coal from and how is it formed?

Answer: We got the coal from the ancient vegetation that was on the earth few millions of years ago. Hundreds of millions years back, there occurred natural calamities like earthquakes, volcanic eruptions due to which the forests were buried under the earth. Soil got deposited on the dead trees, and they were compressed deep inside the earth. Due to the climatic conditions, the buried trees have to undergo different temperature and pressure conditions, and as a result Coal was formed.

4. Can coal, petroleum and natural gas be prepared in the laboratory from dead organisms?

Answer: No. Coal, Petroleum and Natural gas cannot be prepared in the laboratory from dead organisms. Their formation is very slow process and the conditions for their fomation cannot be created in the laboratory.

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TEXT BOOK QUESTIONS

1. What are the advantages of using CNG and LPG as fuels?

Answer: CNG (Compressed Natural Gas) and LPG (Liquefied Petroleum Gas).  Advantages of CNG and LPG fuels are as follows:

1. These fuels are easy to transport (through pipelines).
2. CNG can be directly used for burning in homes and factories where it is supplied through pipelines.
3. They do not have dust particles and they are very clear fuels.
4. They cause less pollution as they do no release smoke when burnt. This less pollution behavior makes them suitable for vehicle.
5. They are also used in the power plants to generate power.
6. LPG is also used as cooking gas.

2. Name the petroleum product used for surfacing of roads.

Answer: Bitumen is the petroleum product used for the Surfacing of roads. Previously coal tar was used for surfacing and metalling the roads. But now a days, bitumen has replaced coal tar.

3. Describe how coal is formed from dead vegetation. What is this process called?

Answer: Hundreds of millions years back, natural calamities like earthquakes and volcanic eruptions have occurred. As a result the forests are buried under the earth. Soil got deposited over the dead trees, and they were compressed deep inside the earth. Due to the climatic conditions, the buried trees are exposed to different temperature and pressure conditions and as a result Coal was formed. This process of conversion of dead trees/vegetation is called carbonization.

4. Fill in the blanks:

1. Fossil fuels are Coal, Petroleum and Natural Gas.
2. Process of separation of different constituents from petroleum is called refining.
3. Least polluting fuel for vehicle is CNG (Compressed Natural Gas).

5. Tick True/False against the following statements:

1. Fossil fuels can be made in the laboratory. False
   (The formation of fossil fuels is a slow process which cannot be achieved in laboratory conditions)
   
2. CNG is more polluting fuel than petrol. False
   (CNG is a clean fuel and thus is less polluting than petrol)
   
3. Coke is almost pure form of carbon. True
   (Coke has less impurities and more carbon content. So it is almost the pure form of carbon)
   
4. Coal tar is a mixture of various substances.True
   (Coal tar is the mixture of about 200 substances)
   
5. Kerosene is not a fossil fuel. False
   (As kerosene is obtained by fractional distillation of crude oil, it is a fossil fuel)
   

6. Explain why fossil fuels are exhaustible natural resources.

Answer: Fossil fuels are exhaustible natural resources because they exist in limited quantity. They are getting exhausted, as the consumption is increasing proportionate to the human population.         

7. Describe characteristics and uses of coke.

Answer: Coke is Tough, porous and black substance. It has very high carbon content. It is used while manufacturing Steel. Further they are used in the extraction of various other metals.

8. Explain the process of formation of petroleum.

Answer: Petroleum is the result of dead bodies of the sea organisms. Dead organism’s bodies were settled deep inside the sea and covered by sand and clay. As there is no oxygen they did not decompose. Over millions of years under high pressure and temperature they got converted into petroleum and natural gas.

9. The following Table shows the total power shortage in India from 1991–1997. Show the data in the form of a graph. Plot shortage percentage for the years on the Y-axis and the year on the X-axis.

Answer:

Line graph representation of total power shortage in India from 1991-1997

Bar graph representation of total power shortage in India from 1991-1997

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