NCERT Class 8 Science Chapter 5 Coal and Petroleum Solutions
NCERT Class 8 Science Chapter 5 Coal and Petroleum Solutions NCERT TEXT BOOK EXERCISES Q. 1. What are the advantages of using CNG and LPG as fuels? Ans. Advantages of LPG as fuel: (i) LPG has a high calorific value. Its calorific value is about 50 kJ/g. (ii) It burns with a smokeless flame and so does not cause any pollution. (iii) LPG is easy to handle and convenient to store. (iv) It undergoes complete combustion. Advantages of CNG as fuel: (i) It does not cause air pollution. (ii) It leaves no ash on burning. Q. 2. Name the petroleum product used for surfacing of roads. Ans. Bitumen. Q. 3. Describe how coal is formed from dead vegetation. What is this process called? Ans. Formation of coal from dead vegetation: About 300 million years ago, there were dense forests in the wet lands that got buried under the surface of the earth due to some environmental changes such as earthquakes, volcanoes and flooding. Gradually, they were covered with many layers of soil and got decomposed. The ...