Students – welcome to Chapter 3 Coal and Petroleum! We have posted excellent solutions to all exercise questions, extended learning activities, in-text questions and activities for this chapter. We have also included self-designed extra questions which resemble actual exam questions. Please study them in detail for maximum benefit. All your questions on Chapter 3 have been answered in this material. Have fun!
Solutions to Exercises (Page No 38) of NCERT Class 8 Science Chapter 3 Coal and Petroleum
1. What are the advantages of using CNG and LPG as fuels?
Answer:
The advantages of using compressed natural gas (CNG) and liquefied petroleum gas (LPG) as fuels are that they can be used directly for burning in homes and factories. They can be transported easily through pipelines. They are clean fuels and do not pollute the environment.
2. Name the petroleum product used for surfacing of roads.
Answer:
The petroleum product used for surfacing or metallic roads is bitumen. It occurs as a solid or viscous liquid and is used in place of coal-tar.
3. Describe how coal is formed from dead vegetation. What is this process called?
Answer:
Coal is formed from dead vegetation that got buried under the soil 300 million years ago. As more soil got deposited over them, they got compressed. The temperature and pressure rose as they sank deeper and deeper, so dead plants slowly got converted into coal. Coal contains mainly carbon, so the process is called carbonisation.
4. Fill in the blanks.
(a) Fossil fuels are ____________, ____________, and __________.
(b) The process of separation of different constituents from petroleum is called _____________.
(c) The least polluting fuel for a vehicle is ______________.
Answer:
(a) Fossil fuels are coal, petroleum, and natural gas.
(b) The process of separation of different constituents from petroleum is called refining.
(c) The least polluting fuel for a vehicle is Compressed Natural Gas (CNG).
5. Tick True/False against the following statements.
(a) Fossil fuels can be made in the laboratory. (T/F)
(b) CNG is a more polluting fuel than petrol. (T/F)
(c) Coke is the most 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)
Answers:
(a) Fossil fuels can be made in the laboratory.
Answer: False. Fossil fuels cannot be made in the laboratory because it takes millions of years and high temperature and pressure for dead organic matter to form fossil fuels.
(b) CNG is a more polluting fuel than petrol.
Answer: False. Compressed Natural Gas is a less polluting and hence cleaner fuel than petrol.
(c) Coke is the most pure form of carbon.
Answer: True. Coke is the most pure form of carbon because coke has a high carbon content ranging from about 90% to 95%.
(d) Coal tar is a mixture of various substances.
Answer: True. Coal tar is a mixture of 200 organic and inorganic compounds.
(e) Kerosene is not a fossil fuel.
Answer: False. Kerosene is a fossil fuel because it is obtained by separating constituents of petroleum which is a fossil fuel.
6. Explain why fossil fuels are exhaustible natural resources.
Answer:
Fossil fuels are exhaustible natural resources because they take millions of years to form and cannot be produced by humans in a laboratory. However, the rate at which they are being used is much faster. At this rate fossil fuels will last only a few hundred years.
7. Describe the characteristics and uses of coke.
Answer:
The characteristics of coke are that it is the purest form of carbon and is a tough, porous and black substance. The users of coke are that is used in the manufacture of steel and in the extraction of many metals.
8. Explain the process of the formation of petroleum.
Answer:
Petroleum was formed by dead sea organisms which died and settled 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 pressure transformed the dead organisms into petroleum and natural gas.
9. The following Table shows the total power shortage in India from 1993–1999. Show the data in the form of a graph. Plot shortage percentage for the years on the Y-axis and the year on the X-axis.
Answer:
The required graph is shown below:
As you can see there is a large increase in power shortage in the more recent years of 1995-1997.
Solutions to Extended Learning – Activities and Projects (Page No 39) of NCERT Class 8 Science Chapter 3 Coal and Petroleum
1. Get an outline map of India. Mark the places in the map where coal, petroleum and natural gas are found. Show the places where petroleum refineries are situated.
Answer:
Solution to Extended Learning Question 1
2. Choose any five families of your neighbourhood. Enquire whether their energy consumption (coal, gas, electricity, petrol, kerosene) has increased or decreased in the last five years. Enquire also about the measures they adopt to conserve energy.
Answer:
Solution to Extended Learning Question 2
3. Find out the location of major thermal power plants in India. What could be the reasons for their being located at those places?
Answer:
Solution to Extended Learning Question 3
Solutions to All Activities of NCERT Class 8 Science Chapter 3 Coal and Petroleum
1. Complete Activity 3.1 (Page 32). Make a list of various materials used by us in daily life and classify them as natural and man-made.
| Natural | Man-made |
Answer:
2. Complete Activity 3.2 (Page 32).
(It is a group activity). Take some containers. Fill them with popcorn/peanuts/roasted gram/toffees. Divide students into
groups of seven each. Further divide each group into three subgroups containing 1, 2 and 4 students. Label them as first, second and third generation respectively. These sub-groups represent the consumers. As population is growing, second and third generations have larger number of consumers.
Put one full container for each group on a table. Ask consumers of the first generation from each group to consume eatables from the container of their group. Now, ask the second generation consumers from each group to do the same. Ask students to observe carefully the availability of eatables in each container. If some thing is left in the containers, ask third generation from each group to consume it. Now, finally observe whether all the consumers of the third generation got the eatables or not. Also observe if anything is still left in any of the containers.
Answer:
Extra Questions to Complement Solutions to NCERT Class 8 Science Chapter 3 Coal and Petroleum –
Very Short Answer Type:
1. What is a natural resource.
Answer:
Resources obtained from nature are called natural resources.
2. Name the purest form of carbon.
Answer:
Coke.
3. Name a thick black liquid obtained from coal.
Answer:
Coal tar.
4. Name a type of fossil fuel derived only from animals.
Answer:
Petroleum is derived only from sea organisms.
5. Name a petroleum product used in metalling roads.
Answer:
Bitumen.
6. Name the coal product which is used as fuel in industries.
Answer:
Coal gas.
7. Where was the world’s first oil well drilled?
Answer:
Pennsylvania, USA.
8. What is petrol and diesel obtained from?
Answer:
Petroleum.
9. Where is petroleum mined from?
Answer:
Petroleum is mined from in between rocks under the earth.
10. Name the most abundant fossil fuel in India.
Answer:
Coal.
Multiple Choice Questions (MCQ):
1. Name the fuel used in heavy motor vehicles.
(a) Coal
(b) Diesel
(c) Petroleum gas
(d) Kerosene
Answer: (b) Diesel
2. Which of the following is considered a relatively clean fuel?
(a) Natural gas
(b) Petrol
(c) Kerosene
(d) Diesel
Answer: (a) Natural gas
3. Name the fuel formed by carbonisation of dead plants.
(a) Natural gas
(b) Coal
(c) Petroleum
(d) All of the above
Answer: (b) Coal
4. How many years does it take to form coal?
(a) Millions of years
(b) Thousands of years
(c) Hundreds of years
(d) Dozens of years
Answer: (a) Millions of years
5. Coal can be used:
(a) To cook food
(b) To produce steam in railway engines
(c) In thermal power plants
(d) As a fuel in various industries
(e) All of the above
Answer: (e) All of the above
Short Answer Type:
1. Give examples of common minerals.
Answer:
Examples of common minerals are calcium, phosphorus, magnesium, sodium, potassium etc.
2. Name some useful products obtained from coal.
Answer:
Coke, coal tar and coal gas are useful products obtained from coal.
3. Why is it sustainable to use solar energy as an energy source?
Answer:
Solar energy is an inexhaustible or renewable energy source. Therefore, unlike coal, petroleum etc solar energy cannot be depleted and is a sustainable energy source.
4. Why does burning of fossil fuels like coal lead to global warming?
Answer:
Burning of fossil fuels releases carbon dioxide (CO2) and other greenhouse gases into the atmosphere. These greenhouse gases trap the suns heat and increase the earth’s atmosphere, which leads to global warming.
5. Name the uses of coal tar.
Answer:
Products obtained from coal tar are used as starting materials for manufacturing various substances used in everyday life and industry like synthetic dyes, drugs, explosives, perfumes, plastics, paints, photographic materials, roofing materials etc. Naphthalene used to repel moths and other insects are also obtained from coal tar.
6. You are given three materials: water, gas and oil inside the earth. Which one comprises the top layer and which one the middle layer?
Answer:
Gas comprises the top layer because it is the lightest of the three materials. Oil comprises the middle layer because it is lighter than water but heavier than gas.
7. What is refining of petroleum?
Answer:
The process of separating the various constituents/fractions of petroleum such as petroleum gas, petrol, diesel, lubricating oil, paraffin wax etc is known as refining.
8. Name three forms of renewable energy.
Answer:
Solar, wind and tidal energy are three forms of renewable energy.
9. What are petrochemicals? What are their uses?
Answer:
Petrochemicals are useful substances are obtained from petroleum and natural gas. They are used in the manufacture of detergents, fibres (polyester, nylon, acrylic etc), polythene and other man-made plastics.
Long Answer Type:
1. What steps would you suggest for the judicious use of fossil fuels? (NCERT Exemplar)
Answer:
The following steps should be taken for the judicious use of fossil fuels:
Energy Efficiency Measures: We should develop energy-efficient technologies and use energy-efficient appliances, vehicles, and industrial processes. This will go a long way in conserving energy for the future.
Energy Conservation: Everyone should work to conserve energy, starting with their own households and offices. Turning off the lights, electric appliances like AC etc when not in use will go a long way in reducing energy consumption.
Adopting Renewable Energy: Investing in and using renewable energy sources, such as solar, wind, tidal, hydroelectric, and geothermal power is vital and will result in decreased use of fossil fuels.
Waste Reduction and Recycling: Recycling ofplastic waste reduces the environmental impact of fossil fuel-related activities.
Sustainability: Promoting sustainable practices in agriculture, forestry, and land use to avoid deforestation and land degradation.
Eco-friendly Transportation: Eco-friendlytransportation such as hybrid and electric vehicles will go a long way in reducing the carbon footprint. The government should give incentives for the use of such transportation.
Education and Awareness: The public should be warned about the environmental impact of fossil fuels and how it can bring about climate change. Individuals should start by educating their family, friends and neighbours and work together to adopt more energy-efficient practices.
Regulatory Frameworks: Regulations should be introduced by the government to control emissions from industries and power plants and incentivize usage of more energy-efficient technology.
2. How should you save petrol and gas while driving?
Answer:
You can save petrol and gas while driving by the following methods:
(i) Driving at a constant and moderate speed as far as possible.
(ii) Switching of the engine at traffic lights and during parking.
(iii) Ensuring correct tyre pressure.
(iv) Regularly maintaining the vehicle.
Fill in the Blanks:
longer, natural, hydrogen, heat, black gold, smaller, exhaustible
(a) Forests are a type of __________ and __________ resource.
(b) Judicious use of fossil fuels will result in _________ risk of global warming and their availability for a __________ period of time.
(c) Petroleum is also known as __________.
(d) _________ gas is obtained from natural gas and is used in the formation of fertilisers.
(e) Nowadays coal gas is used as a source of _________.
Answers:
(a) Forests are a type of natural and exhaustible resource.
(b) Judicious use of fossil fuels will result in smaller risk of global warming and their availability for a longer period of time.
(c) Petroleum is also known as black gold.
(d) Hydrogen gas is obtained from natural gas and is used in the formation of fertilisers.
(e) Nowadays coal gas is used as a source of heat.
Match and Pair:
| Column A | Column B |
| (i) Kerosene | (a) Vaseline |
| (ii) Paraffin wax | (b) Krishna Godavari delta |
| (iii) Air | (c) Aviation fuel |
| (iv) Natural gas | (d) Global warming |
| (v) Burning of fossil fuels | (e) Inexhaustible resource |
Answer:
The completed table is shown below:
| Column A | Column B |
| (i) Kerosene | (c) Aviation fuel |
| (ii) Paraffin wax | (a) Vaseline |
| (iii) Air | (e) Inexhaustible resource |
| (iv) Natural gas | (b) Krishna Godavari delta |
| (v) Burning of fossil fuels | (d) Global warming |
++++++++++++++
Frequently Asked Questions (FAQs) on NCERT Solutions to Class 8 Science Chapter 3 Coal and Petroleum
These solutions have been prepared by expert engineers and scientists, keeping in mind every requirement of the student. All Chapter 3 exercise questions, extended learning activities, in-text questions, in-text activities and even extra questions have been solved in this complete solutions package. We suggest you study them in detail for your exams.
You can download the PDFs of the solutions anytime for free! We will keep posting lot’s more helpful study material and resources, so keep visiting our website and subscribe to our email list to be among the first to access them!
The following topics are covered:
3.1 – Coal
3.2 – Petroleum
3.3 – Natural Gas
3.4 – Some Natural Resources are Limited
Here are the number of problems for the chapter:
(i) 6 Short Answer Type Questions (Questions 1, 2, 3, 6, 7, 8)
(ii) 1 Fill in the Blanks Type Question (Question 4)
(iii) 1 True/False Type Question (Question 5)
(iv) 1 Graph-based Questions (Question 9)
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This chapter contains a lot of fact-based information on coal, petroleum and natural gas. So, study it in detail to be thoroughly prepared for your exams. We have also included many typical exam questions for you to study in the extra questions section. We recommend you study them well and test your knowledge.
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