Class 8 subject
Science
Chapter 5 :- Materials
Coal and Petroleum
(NCERT
Solutions)
1. What are
the advantages of using CNG and LPG as fuels?
Answer:
The advantages CNG and LPG if its use as a fuels are:
They
burn with a complete combustion and smokeless blue flame and so does not cause any pollution.
They
leave no ash or other substance on burning.
They
are easy to handle in cylinder and convenient to store.
2. Name the
petroleum product used for surfacing of roads.
Bitumen
3. Describe how coal is formed from dead vegetation. What is this
process called?
Answer:
according carbonisation process Millions of years ago, trees, plants, of forests got buried below the rocks, soil and sand due to natural processes like
flooding, earthquake, etc. Slowly, as more soil deposited over them, they were
compressed. This led to the conditions of high pressure and heat. These
conditions along with the anaerobic conditions turned the carbon-enriched
organic matter of wood into coal and other substance .
This is process of conversion of wood into coal
is called carbonisation.
4. Fill in the blanks.
(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 vehicle is . ..CNG…
5. Tick True/False against the following statements
(a) Fossil fuels can be made in the
laboratory. (T/F)
FALSE
(b) CNG is more polluting fuel than petrol. (T/F)
FALSE
(c) Coke is almost pure form of carbon.
(T/F)
TRUE
(d) Coal tar is a
mixture of various substances. (T/F)
TRUE
(e) Kerosene
is not a fossil fuel. (T/F)
FALSE