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NCERT Exemplar Solutions Class 8 Science Chapter 5 Coal and Petroleum
For young brains, learning about fossil fuels, how they are extracted, and how they are being replaced by more environmentally friendly energy is critical. This is why the CBSE has included a chapter on coal and petroleum in the Class 8 Science book. It is the fifth chapter that discusses the depletion of non-renewable resources that we use on a daily basis. Science Chapter 5 in Class 8 is an important portion of the curriculum. Refer to the NCERT Exemplar Solutions for Class 8 Science Chapter 5 by Infinity Learn to follow the exercise questions and learn how to solve them.
Download the NCERT Solutions Class 8 Science Chapter 5 answer in PDF format for free and use it offline to swiftly prepare for the chapter. You may rest confident that the answers in this solution are of the greatest quality and will be formatted according to CBSE guidelines. Learn about fossil fuels and other inexhaustible energy sources in this chapter, then use the NCERT Exemplar Solutions for Class 8 Science Chapter 5 to prepare your answers.
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Access Answers to NCERT Exemplar Class 8 Science Solutions for Chapter 5 – Coal and Petroleum
Multiple Choice Questions
- Various materials which are obtained from nature are called natural resources. Which of the following is not a natural resource?
(a) minerals
(b) water
(c) soil
(d) plastic
Answer – (d) plastic
Explanation: Minerals, water, and soil are examples of natural resources, whereas plastic is a synthetic material manufactured by humans. Hence, plastic is not considered a natural resource.
- Air is a natural resource and cannot be exhausted by human activities. It is known as an inexhaustible natural resource. Which of the following is another inexhaustible natural resource?
(a) coal
(b) petroleum
(c) sun-light
(d) minerals
Answer – (c) sunlight
Explanation: Coal, petroleum, and minerals are categorized as non-renewable sources of energy that have the potential to be depleted, unlike sunlight, which is a renewable resource.
- Which of the following is a pair of exhaustible natural resources?
(a) coal and soil
(b) air and sunlight
(c) water and petroleum
(d) wildlife and minerals
Answer – (d) wildlife and minerals
Explanation: Wildlife and minerals are considered exhaustible natural resources due to their limited availability in nature, making them susceptible to depletion through human activities.
- Coal is processed in industries to get some useful products. Which of the following is not obtained from coal?
(a) coke
(b) coal tar
(c) coal gas
(d) CNG
Answer – (d) CNG
Explanation: Under the earth’s surface, natural gas is created through the decomposition of plant material submerged under water.
- Exhaustible natural resources are:
(a) unlimited in quantity.
(b) not dependent on nature.
(c) limited in quantity.
(d) not exhausted by human activities.
Answer – (c) limited in quantity.
Explanation: Finite natural resources exist in limited quantities in nature and can be depleted through human actions. Examples of exhaustible natural resources include coal, petroleum, natural gas, minerals, forests, wildlife, and more.
- Fossil fuels are obtained from:
(a) remains of non-living materials.
(b) dead remains of birds only.
(c) dead remains of insects only.
(d) dead remains of living organisms.
Answer – (d) dead remains of living organisms
Explanation: Fossil fuels are derived from the ancient remains of living organisms, such as plants and animals, that were buried deep within the earth millions of years ago. Coal, petroleum, and natural gas are all classified as fossil fuels.
- Coal is formed from the remains of
(a) vegetation only
(b) animals only
(c) both vegetation and animals
(d) neither vegetation nor animals
Answer – (a) vegetation only
Explanation: Coal originates from the decomposition of extensive terrestrial plants and trees that were buried beneath the earth’s surface approximately 300 million years ago.
- Which substance is formed by the carbonisation of dead vegetation?.
(a) coal
(b) coke
(c) coal gas
(d) coal tar
Answer – (a) coal
Explanation: Coal is created through the carbonization of deceased plant matter.
- Naphthalene balls are obtained from coal tar and are used as:
(a) mosquito repellant
(b) honey bee repellant
(c) moth repellant
(d) snake repellant
Answer – (c) moth repellant
Explanation: Naphthalene balls are tiny spheres of chemical pesticide and deodorant. The distinct odor of naphthalene repels insects and moths, deterring them from areas where naphthalene is placed, such as stored clothing.
- Which of the following is not a constituent of petroleum?
(a) paraffin wax
(b) lubricating oil
(c) petrol
(d) coke
Answer – (d) Coke
Explanation: Coke is not derived from petroleum; instead, it is produced by heating coal in a controlled environment without the presence of air.
- Petroleum was formed from organisms:
(a) living on the land
(b) living on the plants
(c) living in the sea
(d) living on the rocks
Answer – (c) living in the sea
Explanation: Petroleum originated from the decomposition of microscopic plants and animals that were submerged under the sea millions of years ago.
- Choose the incorrect statement from the following:
(a) It is difficult to transport natural gas through pipes.
(b) The disadvantage of natural gas is that it can not be used directly for burning in homes.
(c) Natural gas is stored under high pressure as compressed natural gas.
(d) Natural gas cannot be used for power generation.
Answer – (a) It is difficult to transport natural gas through pipes.
Explanation: Natural gas is a hydrocarbon gas that occurs naturally and is extracted from deep petroleum reserves underground. Due to its high flammability, transporting it through pipelines can be challenging.
Very Short Answer Questions
- You are provided with a mixture of petroleum and water. Can you suggest a method to separate the two?
Answer – Decantation is a method employed to separate a mixture of petroleum and water. The mixture is left to settle, with petroleum rising above the water due to its lighter density. By skillfully pouring off the lighter petroleum layer, it can be separated from the denser water layer without disrupting it.
- What does CNG stand for and why is it considered to be a better fuel than petrol?
Answer – CNG, which stands for Compressed Natural Gas, is regarded as a superior fuel option due to its clean combustion that results in a smokeless flame, causing minimal air pollution. Additionally, when burned, CNG does not emit any harmful or toxic gases.
- Name the petroleum product used as fuel for stoves, lamps and jet aircraft.
Answer –
- Fill in the blanks in the following sentences.
(a) Coal is one of the ________ used to cook food.
(b) When heated in air, coal burns and produces mainly ________ gas.
(c) Coal tar is a black, thick ________ with an ________ smell.
(d) Petroleum, ________ and ________ are fossil fuels.
(e) Forests and coal are ________ natural resources.
Answer – (a) Coal is one of the fuels used to cook food.
(b) When heated in air, coal burns and produces mainly Carbon-di-oxide gas.
(c) Coal tar is a black, thick liquid with an unpleasant smell.
(d) Petroleum, Coal and natural gas are fossil fuels.
(e) Forests and coal are exhaustible natural resources.
- The underlined words in the following sentences have been jumbled up. Write them in their correct form.
(a) Loca is obtained from mines.
(b) Umpetlore is a fossil fuel.
(c) Rineryfe is a place where various fractions of petroleum are separated.
(d) Keenrose is a fuel used in jet crafts.
(e) Nutsgilh is an example of inexhaustible natural resources.
Answer – (a) coal
(b) petroleum
(c) refinery
(d) kerosene
(e) sunlight
- Fill in the blanks.
(a) The slow process of conversion of dead vegetation into coal is called__________.
(b) Coal and petroleum are formed from the dead remains of organisms and are known as __________.
(c) The black thick liquid with __________ smell is known as coal tar.
(d) During the processing of coal to get coke, coal tar and __________ are also obtained.
(e) The process of separating the various constituents of petroleum is known as __________.
(f) Excessive burning of fossil fuels is a major cause of __________.
Answer – (a) The slow process of conversion of dead vegetation into coal is called carbonisation.
(b) Coal and petroleum are formed from the dead remains of organisms and are known as fossil fuels.
(c) The black thick liquid with an unpleasant smell is known as coal tar.
(d) During the processing of coal to get a coke, coal tar and coal gas are also obtained.
(e) The process of separating the various constituents of petroleum is known as refining.
(f) Excessive burning of fossil fuels is a major cause of air pollution.
- Write True/False against the following statements.
(a) Oxygen is an exhaustible natural resource.
(b) Resources which are present in unlimited quantity in nature are called exhaustible natural resources.
(c) Wildlife is an exhaustible natural resource.
(d) Under high temperature and pressure, dead plants get slowly converted to coal.
(e) CNG is less polluting fuel than petrol and diesel.
Answer – (i) Incorrect, oxygen in the air is considered an inexhaustible natural resource as it can be utilized repeatedly.
(ii) Incorrect, resources that exist in limitless quantities in nature are classified as inexhaustible natural resources.
(iii) True
(iv) True
(v) True
Short Answer Questions
- Sunlight and air are inexhaustible natural resources. Comment.
Answer – These resources are abundant in nature and are not prone to depletion due to human activities. They offer an endless supply that can be utilized repeatedly, lasting indefinitely.
- Some natural resources are given in a box. Classify them into the exhaustible and inexhaustible natural resources.
Air, Coal, Natural gas, Sunlight, Petroleum, Minerals, Forests and Oxygen.
Answer – Coal, natural gas, petroleum, minerals, and forests are classified as exhaustible natural resources. On the other hand, air, sunlight, and oxygen are considered inexhaustible natural resources.
| More Resources – NCERT Solutions for Class 8 | |
| NCERT Solutions for Class 8 Science | NCERT Solutions for Class 8 Social Science |
| NCERT Solutions for Class 8 English | NCERT Solutions for Class 8 Maths |
- Write two important uses of coke.
Answer –
(i) Coke serves primarily as a reducing agent in the extraction process of metals such as iron and zinc.
(ii) It plays a crucial role in the production of steel.
- Write the characteristics and some important uses of coal.
Answer –
- Fill in the blanks and complete the story.
About 300 million years ago, the earth had dense ________ in low-lying wetland areas. Due to natural processes, like ______, these forests got buried under the ________. As more ________ deposited over them, they were compressed. The ________ also rose as they sank deeper and deeper. Under high ________ and high ________, dead plants got slowly converted into coal.
Answer – About 300 million years ago, the earth had dense forests in low-lying wetland areas. Due to natural processes, like floods, these forests get buried under the soil. As more soil deposited over them, they were compressed. The temperature also rose as they sank deeper and deeper. Under high pressure and high temperature, dead plants got slowly converted into coal.
- Match the items given in Column I with the items of Column II.
| Column I | Column II |
| (a) Used for road surfacing | (i) Black gold |
| (b) Natural gas | (ii) Vaseline and candles |
| (c) Petroleum | (iii) Bitumen |
| (d) Paraffin wax | (iv) CNG |
Answer – The correct matching is as given:
(a)-(iii), (b)-(iv), (c)-(i), (d)-(ii)
| Column I | Column II |
| (a) Used for road surfacing | (iii) Bitumen |
| (b) Natural gas | (iv) CNG |
| (c) Petroleum | (i) Black gold |
| (d) Paraffin wax | (ii) Vaseline and candles |
Long Answer Questions
- Name the products obtained and their uses when coal is processed in industry.
Answer – When coal is subjected to intense heat in closed retorts without air, it yields valuable products such as coke, coal tar, and coal gas.
Uses of coke include its application in steel manufacturing and metal extraction processes, serving as a superior fuel compared to coal.
Coal tar derivatives are essential raw materials for producing a wide range of everyday and industrial products like synthetic dyes, pharmaceuticals, explosives, perfumes, plastics, paints, photographic materials, roofing supplies, etc. Additionally, naphthalene balls used for insect repellent are derived from coal tar.
Coal gas finds utility as a fuel source in industries located near coal processing facilities.
- We say fossil fuels will last only for a few hundred years. Comment.
Answer – Due to being exhaustible natural resources, fossil fuels are projected to endure for only a few centuries. If consumed at a pace exceeding their natural formation rate, they will deplete rapidly. Once the existing reserves are depleted, there will be no immediate access to new stores of these fossil fuels as their creation from deceased organisms is a process spanning millions of years.
- We read in newspapers that the burning of fuels is a major cause of global warming. Explain why?
Answer – Burning fuels releases gases that trap heat in the atmosphere, causing global warming. This trapped heat raises the Earth’s temperature. When there are more of these gases, like carbon dioxide, it intensifies the warming effect, leading to global warming. This can melt ice and glaciers, raising sea levels.
- While driving, what are the tips we must follow to save petrol/ diesel/natural gas?
Answer – To conserve petrol, diesel, and natural gas, it is important to:
(i) Maintain proper air pressure in the tires.
(ii) Regularly service and maintain your vehicle.
(iii) Drive at a steady and moderate speed whenever feasible.
(iv) Turn off the engine at traffic signals or when waiting to save fuel.
- Imagine that all the exhaustible natural resources are exhausted by human activities. Do you think the survival of living beings would be possible.? If yes, why?, If not, why not?
Answer – If human activities deplete all exhaustible natural resources, the survival of living beings would be jeopardized. Fossil fuels are currently crucial as an energy source, being concentrated and providing heat and light when burned. This heat is utilized for cooking and powering engines like those in automobiles. Additionally, fossil fuels are instrumental in generating electricity, with coal being a common fuel used in power plants.
- Why is petrol an exhaustible natural resource, whereas sunlight is not? Explain.
Answer – Exhaustible natural resources are those that are limited in nature and can be depleted by human activities, such as coal, petroleum, natural gas, minerals, forests, and wildlife. For instance, it takes millions of years for dead organisms to convert into petroleum, which is then refined into petrol. Once the existing stock is depleted, new supplies will not be available in the immediate future. On the other hand, sunlight is abundant in nature and is unlikely to be exhausted by human activities, making it an inexhaustible natural resource.
- Write some important uses of the various constituents of petroleum.
Answer –
(i) Liquid Petroleum Gas (LPG) is utilized as a fuel in households and industries.
(ii) Petrol serves as fuel for cars and aircraft.
(iii) Kerosene is employed as fuel for stoves, lamps, and jet planes.
(iv) Diesel is used as fuel for large vehicles and generators.
(v) Lubricating oil is applied for lubrication purposes.
(vi) Paraffin wax finds application in ointments, candles, and vaseline.
(vii) Bitumen is utilized in road surfacing and paints.
- Coal reserves are said to be enough to last for another hundred years. Do you think we need to worry in such a case? Why or why not?
Answer – Yes, The known coal reserves are estimated to last for approximately 100 years. Once the existing coal resources on Earth are depleted, new supplies of fossil fuels will not be available in the near future, as the process of converting dead organisms into fossil fuels in nature takes millions of years. Therefore, it is crucial to use coal responsibly and avoid wasting it altogether.
- What steps would you suggest for the judicious use of fossil fuels?
Answer –
(i) Fossil fuels should be utilized sparingly, only when essential.
(ii) Natural gas can serve as an alternative. The reserves of natural gas identified have increased tenfold in the past two decades.
(iii) Renewable energy sources like solar, wind, and biomass should be employed instead of fossil fuels.
Also Read: Lakhmir Singh Science Class 8 Solutions Chapter 5 Coal and Petroleum
Class 8 Science Chapter 5 Coal and Petroleum FAQs
In Chapter 5 of NCERT Exemplar Solutions for Class 8 Science, what themes and subtopics are covered?
Chapter 5 of NCERT Exemplar Solutions for Class 8 Science covers the following themes and subtopics: Coal, Natural gas from coal, Tar from coal, Coca-Cola, The use of fossil fuels, Natural gas, Petroleum, Refinery of petroleum.
What are the benefits of using CNG and LPG as fuels in Chapter 5 of NCERT Exemplar Solutions for Class 8 Science?
The following are some of the benefits of using CNG and LPG as fuels: CNG and LPG are both easily combustible. When CNG and LPG are burned, they produce a lot of heat energy. Pipelines make it simple to transfer CNG and LPG. CNG and LPG are non-toxic fuels that do not produce smoke when burned.
In Infinity Learn, how are NCERT Exemplar Solutions for Class 8 Science Chapter 5 design?
The NCERT Exemplar Solutions created by Infinity Learn are highly accurate and appropriate in accordance with the most recent CBSE criteria. These solutions are the best reference materials that students can utilize to prepare for their exams. Students can improve their conceptual knowledge of basic concepts that are crucial for the exam. Each idea also includes examples and a pictorial representation to help students learn visually. Students’ smart learning and efficient replying skills develop as a result of these solutions, resulting in a higher academic score.
