NCERT Solutions for Class 8th Science
Chapter 5. Coal And Petroleum
Text Book Exercise
Text Book Exercise:
Q5. 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) (F), (b) (F), (c) (T), (d) (T), (e) (F).
Q6. Explain why fossil fuels are exhaustible natural resources.
Answer : Fossil fuels are present in nature in limited quantity and are being exhausted abundantly by us. That is why fossil fuels are called exhaustible natural resources.
Q7. Describe characteristics and uses of coke.
Answer : Coke is a tough porous black substance. It is almost pure form of carbon. It is used in the manufacture of steel and in the extraction of many metals.
Q8. Explain the process of formation of petroleum.
Answer : Petroleum is formed from organisms living in the sea. When these organisms died, their bodies settled and the bottom of the sea and got coverd with layers of sand and clay. Over millions of years, they were transformed into petroleum, oil and natural gas under the absence of air and presense of high temperature and high pressure.