CBSE Class 8 Science Chapter-5 Important Questions - Free PDF Download
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Study Important Questions for Class 8 Science Chapter 5 – Coal and Petroleum
Very Short Answer Questions: (1 Marks)
1. When coal burns in air _________ is formed.
A. Carbon Dioxide B. Sulphur Dioxide
C. Carbon Monoxide D. Hydrogen Gas
Ans: A. Carbon Dioxide.
2. Which one of the following is obtained from coal tar?
A. Petrol B. Coke
C. Air D. Naphthalene Balls
Ans: D. Naphthalene Balls
3. Which one of the following is NOT a fossil fuel?
A. Petrol B. Coal
C. WoodD. Diesel
Ans: C. Wood
4. Which one of the following is NOT a non-renewable energy resource?
A. Coal B. Petroleum
C. Solar energy D. Electricity
Ans: C. Solar Energy
5. ___________ is a natural resource.
A. Car B. Bus
C. Water D. Parks
Ans: C. Water
6. Which one is least polluting Fuel?
A. Petrol B. Diesel
C. CNG D. Kerosene
Ans: C. CNG
7. Coal tar contains about ____________.
A. 300 Substance B. 400 Substance
C. 200 Substance D. 100 Substance
Ans: C. 200 Substances
8. Give examples of any two exhaustible resources.
Ans: Coal, petroleum, etc.
9. Give examples of any two inexhaustible resources.
Ans: Sunlight, air, etc
10. Give any two uses of coal.
Ans: Cooking, running rail engines, etc.
11. Name the products of coal.
Ans: Coke, coal tar, coal gas
12. Give any two uses of petroleum.
Ans: Uses of petroleum:
i. It is used to run vehicles.
ii. It is used in petroleum products like Vaseline.
13. Name any two natural gas reserves in India.
Ans: Tripura, Rajasthan, Maharashtra
Short Answer Questions: (3 Marks)
14. What are natural resources? Differentiate between exhaustible and inexhaustible natural resources.
Ans: Resources which we find in our natural environment are called natural resources. Natural resources can be classified into two categories:
These resources are present in limited amounts in nature.
These resources are present in unlimited amounts in nature.
It cannot be replenished after getting exhausted.
It gets replenished after use.
Example: Coal, Petroleum etc.
Example: Water, Sunlight etc.
15. Define fossil fuels
Ans: Fossil fuels are formed by the constant decomposition of dead and decaying animals and plants under pressure and heat in the earth’s crust. Fossil fuel takes thousands of years to form. Example: Coal, Petroleum etc.
16. What is petroleum? How is it formed?
Ans: Petroleum is a type of exhaustible natural resource. Diesel and petrol are obtained from petroleum. Petroleum is found deep inside water in the sea or oceans.
Petroleum is formed from dead organisms which are found in water. The bodies of dead organisms settle at the bottom of the ocean and get covered with soil/sand or other aquatic plants and start decaying slowly. Over millions of years, these dead organisms turn into petroleum or natural gas due to the non-availability of proper oxygen, heat and constant high pressure.
17. What is refining? Why does petroleum require refining?
Ans: The process of separating the various constituents of petroleum at different boiling points is known as refining. Natural petroleum is a crude dark coloured liquid with a very unpleasant smell. It cannot be used in its crude form. Hence, we find petroleum in several different products such as diesel, petrol, wax and use it for various purposes.
18. Name the different constituents of petroleum and write their uses.
Fuel for home and industries.
Motor fuel, Aviation fuel, Solvent for dry cleaning.
Fuel for vehicles and generators.
Ointment, Candle, Wax etc.
Lubrication in machines
Fuel for stove, lamps, jet etc.
19. Why is natural gas a very important fossil fuel?
Ans: Natural gas is important fossil fuel because it mainly constitutes methane and doesn’t produce much pollution. It is a clean gas. Natural gas compressed under high pressure forms CNG which we use in our cars as fuel.
20. State the uses of natural gas.
Ans: Natural gas is used for:
a. Power generation.
b. Fuel for transport vehicles.
c. As a fuel in homes for cooking.
d. Manufacturing of fertilizers and chemicals.
21. Why is natural gas preferred over petrol as a transport fuel?
Ans: Natural gas is preferred over petrol because it is a clean-burning fuel and produces less harmful substances into the air.
Long Answer Questions: (5 Marks)
22. Explain in detail the products of coal.
Ans: Coal is processed in the industry to get some useful products such as coke, coal tar and coal gas.
(a) Coke: Coke is almost a pure form of carbon. It is dark in colour. It is used for the extraction of metals.
(b) Coal Tar: It is a black liquid with a very unpleasant smell. It is a by-product obtained during the formation of coke. Coal tar is a major constituent during the manufacturing of paints or anti-dandruff shampoos.
(c) Coal Gas: Coal gas is also obtained during the formation of coke.
23. Why should we use some resources like coal and petroleum in limit?
Ans: Resources like coal and petroleum are from exhausting natural resources. They are formed by the decomposition of dead organisms over millions of years. Their replenishment rate is very slow. Also, this fossil fuel produces carbon dioxide on burning which is very harmful to our environment causing air pollution as well as global warming. Hence, we should use coal and petroleum in limited amounts.
24. Suggest ways in which consumption of fuels can be reduced.
Ans: Petroleum Conservation Research Association (PCRA) advises people on how to save petrol/diesel while driving. This will also help in the reduction of air pollution.
Some of the ways are as follows:
Use more renewable sources of energy such as CNG.
Switch off the engine of the vehicle at traffic lights or in long jams.
Ensure regular maintenance of the vehicle.
We can use bicycles for a small distance.
Importances of Important Questions for CBSE Class 8 Science Chapter 5- Coal and Petroleum
The importance of having a set of important questions for CBSE Class 8 Science Chapter 5, "Coal and Petroleum," cannot be overstated. These questions serve as invaluable tools for students studying this crucial topic.
Firstly, they offer a structured approach to learning, helping students identify and focus on the key concepts within the chapter. This ensures that they grasp the fundamental principles of the formation, extraction, and uses of coal and petroleum.
Secondly, by answering these questions, students engage in active learning, which is essential for retention and understanding. Furthermore, important questions aid in exam preparation by providing a clear outline of the topics that are likely to be covered in assessments.
They enable students to evaluate their knowledge and pinpoint areas that require further study. In essence, important questions enhance the learning experience, making the complex subject of coal and petroleum more accessible and facilitating better academic performance.
In conclusion, the compilation of important questions for CBSE Class 8 Science Chapter 5, "Coal and Petroleum," holds significant educational value. These questions serve as indispensable aids in the study of this critical subject. They provide a structured approach to learning, enabling students to focus on essential concepts related to the formation, extraction, and uses of coal and petroleum. Moreover, these questions facilitate active learning, reinforcing understanding and retention. As valuable tools for exam preparation, they help students prioritize their study efforts and assess their knowledge effectively. In essence, important questions enrich the learning experience, making the complex topics of coal and petroleum more accessible and contributing to better academic performance.
FAQs on Important Questions for CBSE Class 8 Science Chapter 5 - Coal and Petroleum
Q1. How is energy useful to us?
Ans: Our life is impossible without energy. It is needed in almost every field of our life. Energy is useful for many purposes like:
To generate electricity and to run vehicles, we need energy from fuels.
For electrical appliances like refrigerators, TVs, radios, and computers.
Energy is required at construction sites to build houses and buildings.
Energy is needed to cook our food and for other domestic use.
We need energy like petrochemicals for manufacturing plastics, paints, fibres, and cosmetics.
To run the machines, power supply is needed in all the factories, industries and agricultural devices.
Q2. Why is petrol an exhaustible natural resource, whereas sunlight is not?
Ans: Petrol is a fossil fuel which requires millions of years to form from the decomposition of buried and plants deep down the earth. It is limited in quantity and can be exhausted by human activities. So, petrol is an exhaustible natural resource but sunlight is an inexhaustible and renewable natural resource as it will continue to radiate energy and present in unlimited quantity. Sunlight cannot be exhausted by human activities.
Q3. What are the steps to conserve the resources?
Ans: We all depend on the resources for various purposes but they are limited in nature. It's our responsibility to conserve them for future use. We should all follow the golden rule of conservation - 3 R’s - Reduce, Reuse and Recycle. Electricity devices that consume less energy should be used at home. Cook on low flame. Switch off lights and fans when not in use and save electricity. Use public transport as much as possible. Solar and Tidal energy should be encouraged and developed as they are unlimited in nature. Instead of burning coal or petroleum to generate electricity, dams should be used.
Q4. Explain the advantages and disadvantages of using petroleum?
Ans: The advantages of using Petroleum are it is easy to extract at a low cost. It can be stored and transported easily over long distances. By using existing technology, spills and leaks can be controlled. It is a high density fuel. It provides a stable energy resource. It is extremely flexible as a raw material in chemical synthesis. The disadvantages are it is limited and non-renewable form of energy. It causes environmental pollution as combustion releases dangerous gases. To learn more about the topic, refer to the Important Questions for CBSE Chapter 5 - Coal and Petroleum of Class 8 Science provided by Vedantu. These are available on both the website and the App free of cost.
Q5. Explain why the burning of fossil fuels causes air pollution.
Ans: A lot of air pollution is caused due to burning of fossil fuels. For example, gases like carbon dioxide, carbon monoxide, sulphur dioxide, etc are produced when coal is burnt. This may bring undesirable changes in climate due to the increase of the greenhouse effect. When petrol is burnt in automobiles, major air pollutants are produced like carbon monoxide, sulphur dioxide, etc. All these pollutants are harmful to human beings and living organisms. It can cause breathing problems and skin diseases.