Class 8 Science Lesson 5 Inside Question and Answer NCERT & CBSE Board Here in this post. NCERT Class 8 Science Textbook Lesson 5 Inside Questions.
- Grade: VIII
- Lesson 5 Coal and Petroleum
Que. 1) fill in the blanks.
(1) —– is obtained during the processing of coal to get coke.
Ans- Coal gas
(2) —– is black and thick liquid.
Ans- coal tar.
(3) —- is used for power generation.
(4) Lubricants oil is used for ——
Ans – lubrication.
Que. 2) answers the followings question-
(1) Define the followings
(a) Fossil fuels-There are some coal ,natural gas or petroleum are formed from the dead remains of living organism these are known as fossil fuels.
(b) Petroleum refinery –the process of separating the various constituents /fractions of petroleum is known as petroleum refining.
(c) Petroleum- petrol and diesel are obtained from a natural resource called petroleum.
(2) Give difference between inexhaustible natural resources and exhaustible natural resource.
|Inexhaustible natural resources||Exhaustible natural resources|
|These resources are present in unlimited quantity in nature and are not likely to be exhausted by human activities .||The amount of these resources in nature is limited. They can be exhausted by human activities|
|For eg. Sunlight, air.||For eg. Petroleum, natural gas, minerals, coal.|
(3) Write about natural gas.
Ans- natural gas is very important fossil fuel because it is easy to transport though pipes. Natural gas is stored under high pressure as compressed natural gas(CNG). CNG is used for power generation. It is now being is used as a fuel for transport vehicles because it is less polluting. Natural gas is used for starting material for the manufacture of a number of chemicals and fertilizers.India has vast reservrrs of natural gas. India natural gas is found in Tripura, Rajasthan, Maharashtra and in the Krishna Godavri delts.
(4) Write short note on followings:
Coal- It is hard as stone and is black colour. Coal is one of the fuels used to cook food. Earlier, it was used in railway engines to produce steam to run the engine. It is also used in thermal power plants to produce electricity. Coal is used as fuel in various industries when heated in air coal burns and produces mainly carbon dioxide gas. Coal is processed in industry to get some useful products such as coke, coal tar and coal gas.
Coke– It is a tough, porous and black substance. It is an almost pure form of carbon. Coke is used in the manufacture of steel and in the extraction of many metals.
Coal tar-It is black, thick liquid with an unpleasant smell. It is a mixture of about 200 substances. Products obtained from coal tar are used as starting materials for manufacturing various substances used in everyday life and in industry like synthetic dyes, drugs, explosives, perfumes, plastics, paints, photographic materials, roofing materials etc. naphthalene balls used to repel moths and other insects are also obtained from coal tar.
Coal gas- Coal gas is obtained during the processing of coal to get coke. It is used as a fuel in many industries situated near the coal processing plants. Coal gas was used for street lighting for the first time in London in 1819 and in New York around 1820. It is also used as a source of heat rather than light.
(5) Write any five constituents of petroleum and their uses.
Ans- constituents and there uses as below-
Constituents of petroleum
Petroleum gas in Liquid from (LPG)
|Fuel for home and industry.|
|Motor fuel, aviation fuel, solvent for dry cleaning.|
Fuel for stoves, lamps.
Ointments, candles ,Vaseline etc.
(6) How petroleum is formed?
Ans- petroleum is formed from organisms living in the sea. As these organisms died, their bodies setteled at the bottom of the sea and got covered with layers of sand and clay. Over millions of years, absence of air, high temperature and high pressure transformed the dead organisms into petroleum and natural gas.