Question 1: What
are the advantages of using CNG and LPG as fuels?
Answer: The
advantages of using compressed natural gas (CNG) and liquified petroleum gas
(LPG) as fuels are:
(i) They can be burnt directly.
(ii) They can be transported easily through pipe lines.
(iii) They are clean fuels and do not give smoke when burnt.
(iv) They give a lot of heat energy when burnt.
Question 2: Name
the petroleum product used for surfacing of roads.
Answer: Bitumen,
a petroleum product, is used for surfacing roads.
Question 3: Describe
how coal is formed from dead vegetation. What is this process called?
Answer: Millions
of years ago, dense forests got buried under the soil due to natural processes
like storms, floods, and earthquakes. These got compressed as more and more
soil got deposited over them. When they got buried deep in the soil, they were
exposed to very high pressure and temperature. Under these conditions, these
slowly got converted into coal. This process of formation of coal from dead
vegetation is called carbonization.
Question 4: Fill
in the banks.
(a) Fossil fuels are ________, ________ and _________.
(b) Process of separation of different constituents from
petroleum is called _________.
(c) Least polluting fuel for vehicles is __________.
Answer: (a)
Fossil fuels are __coal__, __petroleum__ and __natural gas__.
(b) Process of separation of different constituents from
petroleum is called __refining__.
(c) Least polluting fuel for vehicles is __compressed
natural gas (CNG)__.
Question 5: Tick
True/False against the following statements.
(a) Fossil fuels can be made in the laboratory. (T / F)
(b) CNG is more polluting fuel than petrol. (T / F)
(c) Coke is almost pure form of carbon. (T / F)
(d) Coal tar is a mixture of various substances. (T / F)
(e) Kerosene is not a fossil fuel. (T / F)
Answer: (a)
Fossil fuels can be made in the laboratory. (F)
(b) CNG is more polluting fuel than petrol. (F)
(c) Coke is almost pure form of carbon. (T)
(d) Coal tar is a mixture of various substances. (T)
(e) Kerosene is not a fossil fuel. (F)
Question 6: Explain why fossil fuels are exhaustible
natural resources.
Answer: Fossil
fuels require millions of years to form from the dead vegetation and animals
that get buried deep inside the Earth. They require high temperature and
pressure for their formation, which cannot be provided in the laboratory. Thus,
fossils are limited. Therefore, the use of fossil fuels at this rate will lead
to their exhaustion.
Question 7:: Describe
characteristics and uses of coke.
Answer: Characteristics
of coke are:
(i) Tough
(ii) Porous0
(iii) Black in colour
Uses of coke: (i) In manufacture of steel. (ii) In
the extraction of metals (as a reducing agent).
Question 8: Explain
the process of formation of petroleum.
Answer: Petroleum
was formed from dead organisms that got buried in the sea millions of years
ago. These dead bodies got covered with layers of sand and clay. Lack of air,
high temperature, and high pressure transformed these dead organisms into
petroleum and natural gas.
Question 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.
S. No.
|
Year
|
Shortage (%)
|
1
|
1991
|
7.9
|
2
|
1992
|
7.8
|
3
|
1993
|
8.3
|
4
|
1994
|
7.4
|
5
|
1995
|
7.1
|
6
|
1996
|
9.2
|
7
|
1997
|
11.5
|
Answer:
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