chapter 5 class 8th DAV board Question/Answer Science
Answers
Explanation:
What is refining? Why does petroleum require refining?
Ans. The process of separating the various constituents/ fractions of petroleum is
known as refining. Petroleum is a dark oily liquid. It has an unpleasant odour. It is a mixture of various constituents such as petroleum gas, petrol, diesel, lubricating oil, paraffin wax, etc. Therefore, it requires refining
Name the different constituents of petroleum and write their uses Nu
Constitute of Petroleum
Petrol
Diew
Puct home and industry
by cleaning
5. Ans
Why is natural gas a very important fossil fuel? Ans Natural gas is a very important fossil fuel because it is easy to transport through pipes. Natural gas is stored under high pressure as compressed natural gas (CNG).
State the uses of natural gas Ans Natural gas is used for:
a. Power generation
b. Fuel for transport vehicles c. Burning in homes and factories
d. Manufacturing of fertilizers and chemicals
Why is natural gas preferred over petrol as a transport fuel? Ans Natural gas is preferred over petrol as a transport fuel because it is less polluting and a cleaner fuel than petrol.
Long Answer Questions
1 Explain in detail the products of coal
Ans. Coal is processed in industry to get some useful products such as coke, coal tar and coal gas.
a. Coke It is a tough, porous and black substance. It is an almost pure form of carbon. Coke used in the manufacture of steel and in the extraction of many metals.
b. Coal Tar
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