Coal and Petroleum Class 8 Science Extra Questions and Answers
Coal and Petroleum Class 8 Science Chapter 5 Extra Questions and Answers are provided here. We prepared these extra questions based on the latest NCERT Class 8 Science Book. CBSE Class 8 Science Chapter 5 Coal and Petroleum Extra Questions will help you to properly understand a particular concept of the chapter.
Class 8 Science Chapter 5 Coal and Petroleum Extra Questions
Very Short Answer Type Question
Question 1: Why LPG is a better fuel than coal?
Answer: LPG is a better fuel than coal because it is a cleaner fuel.
Question 2: Name the petroleum product used for surfacing of roads.
Answer: Bitumen, a petroleum product, is used for metalling the roads.
Question 3: What are natural resources?
Answer: Materials obtained from nature are called natural resources.
Question 4: What are the characteristics of coal?
Give two characteristics of coal.
Answer: It is as hard as stone and is black in colour.
Question 5: Which fuel is used in heavy motor vehicles?
Answer: Diesel is used in heavy motor vehicles.
Question 6: Where and when was the world’s first oil well drilled?
Answer: The world’s first oil well was drilled in Pennsylvania, USA, in 1859.
Question 7: What are the uses of kerosene?
Answer: Kerosene is used as fuel in stoves, lamps and in jet aircrafts.
Question 8: Why is lubricating oil used?
Answer: Lubricating oil is used for lubrication.
Question 9: Write the uses of paraffin wax.
Answer: Paraffin wax is used in ointments, candles, vaseline etc.
Question 10: From where do we obtain petrol and diesel?
Answer: Petrol and diesel are obtained from a natural resource called petroleum.
Question 11: How can bitumen be used?
Write uses of bitumen.
Answer: Bitumen can be used for making paints and for surfacing the roads.
Question 12: Give two uses of diesel.
Write two uses of diesel.
Answer: Diesel is used as fuel for heavy motor vehicles and in electric generators.
Question 13: Why is petroleum also known as ‘black gold’?
Answer: Due to its great commercial importance, petroleum is also called ‘black gold’.
Question 14: How can petrol be used?
Write two uses of petrol.
Answer: Petrol can be used as a motor fuel, aviation fuel and as solvent for dry cleaning.
Question 15: Can coal, petroleum and natural gas be prepared in the laboratory from dead organisms?
Answer: No. Their formation is a very slow process and conditions for their formation cannot be created in the laboratory.
Question 16: Name two places in India where petroleum is found.
Where is petroleum found in the India?
Answer: In India, oil is found in Assam, Gujarat, Mumbai High and in the river basins of Godavari and Krishna.
Question 17: What are the products obtained on refining petroleum?
Answer: Petroleum gas, petrol, diesel, kerosene, paraffin wax, lubricating oil are obtained by refining petroleum.
Question 18: Why are coal and petroleum called fossil fuels?
Answer: Coal and petroleum are called fossil fuels because it required the dead organisms millions of years to get converted into these fuels.
Question 19: Name some places in India where natural gas has been found.
Where do we find natural gas in India?
Answer: In India, natural gas is found in Tripura, Rajasthan, Maharashtra and in the Krishna Godavari delta.
Short Answer Type Questions
Question 1: How were fossils formed? Name two fossil fuels.
Answer: Fossil fuels were formed from the dead remains of living organisms millions of years ago. Coal, petroleum and natural gas are fossil fuels.
Question 2: What are the three zones of flame?
Answer: There are three different zones of a flame – innermost zone (dark zone), middle zone (luminous zone) and outer zone non-luminous zone.
Question 3: What is combustion? Give example.
Answer: A chemical process in which a substance reacts with oxygen to give off heat is called combustion. Example: Burning of charcoal.
Question 4: Why food is called fuel for our body?
Answer: Food is called fuel for our body because in our body food is broken down by reaction with oxygen and heat is produced.
Question 5: Why is the innermost zone of a flame black in colour?
Answer: The innermost zone of a flame is black in colour due to presence of unburnt vapours of the combustible material.
Question 6: Explain how CO2 is able to control fires.
Answer: CO2, being heavier than oxygen, covers the fire like a blanket. Since the contact between the fuel and oxygen is cut off, the fire is controlled.
Question 7: Which is the best fire extinguisher for fires involving electrical equipment and inflammable materials like petrol?
Answer: For fires involving electrical equipment and inflammable materials like petrol, carbon dioxide (CO2) is the best extinguisher.
Question 8: Why is water not used to control fires involving electrical equipment?
Explain why fire caused by electricity should not be extinguished by pouring water?
Why water is not suitable for extinguishing fire caused due to electrical appliances?
Why can we not use water to extinguish fire caused due to electrical appliances?
Answer: Water is not used to control fires involving electrical equipment because water may conduct electricity and harm those trying to douse the fire.
Question 9: What are the harmful products released by the burning of fuels?
Answer: The harmful products released by the burning of fuels are unburnt carbon particles, carbon monoxide, carbon dioxide, sulphur dioxide, nitrogen oxides etc.
Question 10: What is rapid combustion? Give one example.
Answer: The combustion that takes place rapidly and produces heat and light is called rapid combustion. Example: Gas burns rapidly and produces heat and light.
Question 11: Why are fires produced by burning oil not extinguished by pouring water?
Water is not suitable for fires involving oil and petrol. Explain.
The fire produced by petrol cannot be extinguished by using water. Explain why?
Answer: Water is heavier than oil. So, it sinks below the oil, and oil keeps burning on top. Thus, water is also not suitable for fires involving oil and petrol.
Question 12: What causes global warming?
Answer: Combustion of most fuels releases carbon dioxide in the environment. Increased concentration of carbon dioxide in the air is believed to cause global warming.
Question 13: What are the effects of global warming?
Answer: Global warming results in the melting of polar glaciers, which leads to a rise in the sea level, causing floods in the coastal areas. Low lying coastal areas may even be permanently submerged under water.
Question 14: What is combustible substance? Give some examples.
Answer: The substance that undergoes combustion is said to be combustible substance.
Some of the combustible substances are wood, coal, charcoal, paper, dry leaves, petrol etc.
Question 15: What is non-combustible substance? Give some examples.
Answer: The substance that does not burn is said to be non-combustible substance. Some of the non-combustible substances are soil, stone, glass, water etc.
Question 16: Can you burn a piece of wood by bringing a lighted matchstick near it? Explain.
Answer: The ignition temperature of a piece of wood is high which cannot be reached by the small heat produced by a burning matchstick. So, a matchstick cannot light (or burn) a piece of wood directly.
Question 17: How forest fires occur during the hottest summer days?
Why do forest fires occur during hot summers?
Answer: During hot summers, sometimes the ignition temperature of dry grass in the forest is reached, which makes the dry grass catch fire. From grasses, it spreads to trees, and very soon the whole forest is on fire.
Long Answer Type Questions
Question 1: State some characteristics of petroleum.
Answer: Characteristics of petroleum
- It is a dark oily liquid.
- It has an unpleasant odour.
- It is a mixture of various constituents such as petroleum gas, petrol, diesel, lubricating oil, paraffin wax, etc.
Question 2: Explain the process of the formation of petroleum.
How is natural gas formed?
Answer: Petroleum was formed from organisms living in the sea. As these organisms died, their bodies settled at the bottom of the sea and got covered with layers of sand and clay. Over millions of years, the absence of air, high temperature, and high pressure transformed the dead organisms into petroleum and natural gas.
Question 3: Write uses of coal tar.
Answer: Products obtained from coal tar are used as starting materials for manufacturing various substances used in everyday life and in industry, like synthetic dyes, drugs, explosives, perfumes, plastics, paints, photographic materials, roofing materials, etc. Interestingly, naphthalene balls used to repel moths and other insects are also obtained from coal tar.
Question 4: What are the uses of coal?
State some uses of coal.
Answer: Uses of coal are as follows
- Coal is one of the fuels used to cook food.
- Earlier, it was used in railway engines to produce steam to run the engine.
- It is also used in thermal power plants to produce electricity.
- Coal is also used as a fuel in various industries.
Question 5: What are the advantages of using CNG and LPG as fuels?
Answer: The advantages of using CNG and LPG as fuels are:
- They can be transported easily through pipes.
- They can be used directly for burning in homes and factories where it can be supplied through pipes.
- They are clean fuels and do not give smoke when burnt.
- They are less polluting.
Question 6: State some of the tips of PCRA to conserve petrol and diesel.
Give the tips advised by PCRA to save petrol/diesel while driving.
Answer: Their tips are:
- Drive at a constant and moderate speed as far as possible,
- Switch off the engine at traffic lights or at a place where you have to wait,
- Ensure correct tyre pressure, and
- Ensure regular maintenance of the vehicle.
Question 7: Describe how coal is formed from dead vegetation. What is this process called?
Where do we get coal from and how is it formed?
Answer: About 300 million years ago the earth had dense forests in low lying wetland areas. Due to natural processes, like flooding, these forests got 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 to coal. As coal contains mainly carbon, the slow process of conversion of dead vegetation into coal is called carbonisation.
Question 8: Distinguish between inexhaustible and exhaustible natural resources.
|Inexhaustible Natural Resources||Exhaustible Natural Resources|
|These resources are present in unlimited quantity in nature and are not likely to be exhausted by human activities.||The amount of these resources in nature is limited. They can be exhausted by human activities.|
|Examples of these resources are sunlight and air.||Examples of these resources are forests, wildlife, minerals, coal, petroleum, natural gas etc.|
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