Coal and Petroleum

Question 1.
Name some renewable sources of energy.
Answer:
Water, wind, solar.

Question 2.
Give some examples of fossil fuels.
Answer:
Coal, petroleum, natural gas.

Question 3.
Name the elements present in coal.
Answer:
Carbon, oxygen and sulphur.

Question 4.
Which are the two main techniques of mining?
Answer:
Surface mining and underground mining.

Question 5.
List four varieties of coal.
Answer:
Peat, lignite, bituminous, anthracite.

Question 6.
Name the process of conversion of wood into coal.
Answer:
Carbonisation

Question 7.
Mention the temperature at which destructive distillation is done.
Answer:
1000°C

Question 8.
When the crude oil is referred to be ‘sweet’?
Answer:
If the sulphur content is low.

Question 9.
Name the process of conversion of kerogen into gaseous hydrocarbons.
Answer:
Catagenesis

Question 10.
Name the country which is the leading producer of petroleum.
Answer:
Saudi Arabia

Question 11.
Name the gas that occurs over petroleum in reservoirs deep inside the earth.
Answer:
Natural gas
Question 12.
Expand PCRA.
Answer:
Petroleum Conservation Research Association.

Question 13.
Name two fractions of petroleum which are used as fuel.
Answer:
Petrol and diesel

Question 14.
What kind of pollution is caused by the burning of fossil fuels?
Answer:
Air pollution

Question 15.
Write the full form of LPG.
Answer:
Liquefied Petroleum Gas.

Question l6.
Which gas is produced when coal is burnt in air?
Answer:
Carbon dioxide

Question 17.
Can we use all our natural resources forever?
Answer:
No

Question 18.
What is the purest form of carbon?
Answer:
Coke

Question 19.
Where and when was the first oil well drilled?
Answer:
Pennsylvania, USA in 1859.

Question 20.
Name the places where natural gas is found in our country.
Answer:
Tripura, Rajasthan, Krishna Godavari Delta, Maharashtra, etc.

Coal and Petroleum Class 8 Extra Questions Short Answer Questions

Question 1.
What is fuel?
Answer:
Anything that burns to produce energy in an efficient manner is called a fuel.

Question 2.
Define fossil fuels. Give examples.
Answer:
Natural fuels that are made up by burial of living organisms under deep down the earth for over a long period of
time, are called fossil fuels.
For example, coal, petroleum, natural gas.
Question 3.
What is coal? Write its two uses.
Answer:
Coal is a hard, black combustible substance that mainly contains carbon.
Uses:

 It is used as a fuel in homes and industry.

 It is used as a fuel at Thermal Power Plants for generating electricity.

Question 4.
Give a brief description about peat.
Answer:
Peat is the most inferior and softest form of coal. Its carbon content is very low. It has a large amount of moisture and
is not much suitable to be used as fuel. Its carbon content is 20 – 25%.

Question 5.
Name three constituents of petroleum and write their uses also.
Answer:
The three constituents of petroleum are:

 petrol

 paraffin wax

 diesel

Uses:

 Petrol: It is used as a motor fuel and for dry cleaning.

 Paraffin wax: It is used for making ointments, candles, vaseline, etc.

 Diesel: It is used as a fuel for heavy motor vehicles and electric generators.

Question 6.
Explain about coal tar.
Answer:
It is produced when the gases are evolved due to heating of coal in water. It is a black-coloured, thick, viscous liquid.
It has a pungent smell. It is itself a mixture of many compounds. We can get benzene, toluene, napthalene, phenol,
etc., from coal tar.

Question 7.
Name two products that you obtain from the destructive distillation of coal. What is the residue left in’ this process?
Give one main use of this residue.
Answer:
The two important products obtained from the destructive distillation of coal are: Coal gas and coal tar. The residue
left in this process is coke. Coke is used mainly as a reducing agent in the extraction of metals.

Question 8.
Where do we get coal and how is it formed?
Answer:
We get coal deep in the earth’s crust in coal mines. It is formed by the slow decomposition of dead trees and other
vegetable matter buried deep under the earth’s crust under high pressure and temperature.

Question 9.
Define the term ‘petrochemicals’.
Answer:
Petrochemicals are the substances obtained from petroleum and natural gas. They are used in the manufacture of
detergents, fibres, polythene, etc.

Question 10.
What is CNG? What are its uses?
Answer:
CNG is short form of Compressed Natural Gas. Natural gas is stored under high pressure as CNG. CNG is used for
power generation. It is now being used as a fuel for transport vehicles because it is less polluting. It is a cleaner fuel.

Coal and Petroleum Class 8 Extra Questions Long Answer Questions

Question 1.
Explain about the varieties of coal.
Answer:
Depending upon the amount of carbon content, coal may be of four types:

 Peat: This is the most inferior and softest form of coal. Its carbon content is very low. It has a large amount of
moisture and is not much suitable to be used as fuel.

 Lignite: Lignite is comparatively harder than peat, but still is very soft. Its carbon content is more than that of
peat.

 Bituminous: Its carbon content is higher, as it is free from moisture and other impurities.

 Anthracite: This is the highest grade coal. This is also known as hard coal. It has maximum amount of carbon.
It produces a very little smoke.

Question 2.
The burning of fossil fuels causes air pollution. Explain.
Answer:
The burning of fossil fuels causes a lot of air pollution.
The burning of coal produces gases like carbon dioxide, carbon monoxide, sulphur dioxide, etc., which can lead to
undesirable changes in climate due to increase greenhouse effect.

The major air pollutants produced by the burning of petrol in automobiles are carbon monoxide, sulphur dioxide,
unbumt hydrocarbons, etc. These pollutants are harmful for human beings and living organisms which causes
breathing problems and skin diseases.

Question 3.
Write a short note on petroleum.
Answer:
Petroleum is the liquid form of fuel. It is also known as crude oil and found trapped between the layers of impervious
rocks under the ground. It is a natural resource, which formed by the dead plants and animals in the sea. It is a dark
coloured viscous liquid and like all other oils, it is lighter than water. It is a mixture of different hydrocarbons. It
undergoes fractional distillation to yield petrol, kerosene, diesel and other chemicals used in manufacture of plastics.

Question 4.
How is the energy useful to us? Explain.
Answer:
We need energy in almost every field of our life. Without energy our life is impossible. Some of the uses of energy
are:

 We need energy of fuels to generate electricity and to run vehicles.

 We need energy to run our electrical appliances like refrigerator, TV, radio, computer, etc.

 We need energy at construction sites to construct houses, buildings, etc.

 We need energy to cook our food and other domestic use.

  We need energy (petrochemicals) for manufacturing fibres, plastics, paints, cosmetics, etc.

 All the factories, industries, agricultural devices depend on power supply to run the machines.

Question 5.
List the steps to conserve the resources.
Answer:
As we know, we all are dependent on the resources. But we should keep in mind that resources are limited in nature.
If we misuse it, our future generation will have no resources. This is an alarming situation.
We can take following steps:

 We shbuld cook our food on low flame.

 Devices that consume less energy like CFLs and LED lights should be preferred.

 We should take care not to waste electricity.

 We should cover our cooking vessels while cooking.

 Instead of use of individual vehicles, use of public transport should be encouraged.

 Solar or tidal energy should be developed and encouraged.

 Dams should be use to generate electricity instead of burning coal or petroleum.

 Public awareness programmes should be conducted.

Coal and Petroleum Class 8 Extra Questions Higher Order Thinking Skills

Question 1.
You are provided with a mixture of petroleum and water. How will you separate the two?
Answer:
Allow to stand the mixture of petroleum and water undisturbed for some time. The top layer will be consisted of
petroleum which can be separated from water by decantation.

Question 2.
Differentiate between coke and coal.
Answer:

Coke Coal

(i) It is an amorphous form of carbon. (i) It is a non-crystalline form of carbon.

(ii) It is obtained by heating soft coal in absence or limited (ii) It is obtained by the decay of vegetation which existed
supply of air. millions of years ago.

Question 3.
None of the fuels is clean fuel. Comment.
Answer:
On burning, every fuel releases atleast C02 which causes greenhouse effect. Thus none of the fuels are clean.

Question 4.
Can forests help reduce the pollution caused by burning of fossil fuels? How?
Answer:
Not all, but yes it reduces some of the pollution like carbon dioxide emitted during burning of fossil fuels.

Question 5.
What other source of energy may be used to drive vehicles?
Answer:
Biodiesel, ethanol, solar energy.

Coal and Petroleum Class 8 Extra Questions Value-Based Questions

Question 1.
Radhey prefers to go to school by pooling car. On other occasions he like to opt for public transport rather than
private transport. For short distances, he walks or uses bicycle.
(a) What are the benefits of carpooling?
(b) Which mean of transport do you think is best for short distances?
(c) How on our end we can reduce the consumption of fossil fuels?
(d) What values of Radhey are shown here?
Answer:
(a)

 Cost effective

 Reduces pollution

 Reduces traffic on roads

 Saves fossil fuels

(b) Bicycle
(c)

 By reducing use of plastics as these are products of fossil fuels.

 By consuming electrical energy judiciously as most of the electricity comes from burning coal.

 By carpooling. As car uses petrol or diesel—a form of fossil fuel.

 Switching engine off at red lights.

(d) Radhey is eco-friendly, environmentally conscious and works judiciously.

Question 2.
There was an essay-writing competition on ‘How to Reduce your Carbon Footprint’ in Satish’s school. Satish enquired
his best on this topic to his elders and searched internet. He got the first prize in the competition.
(a) What do you understand by the term ‘Carbon Footprint’?
(b) Suggest ways to reduce your carbon footprint.
(c) What values of Satish are shown here?
Answer:
(a) The total amount of greenhouse gases produced by an individual, organisation or event is known as ‘Carbon
Footprint’.
(b)

 Follow 3R’s, i.e., – reduce, reuse and recycle.

 Use public transport and carpool.

 Avoid traffic.

 Plant trees.

 Use energy efficient appliances.

(c) Satish is inquisitive, intelligent, hard working and sincere boy.

Activities and Projects

Question 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:

Question 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:
Do it yourself.

Question 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:
Major thermal power plants in India are located in Uttar Pradesh, Gujarat, West Bengal, Odisha, Chhattisgarh and
Madhya Pradesh. The reason for their being located at those places is the presence of majority of coal mines nearer
to them.

I. Multiple Choice Questions (MCQs)

Choose the correct option.
Question 1.
Which of the following is a renewable source of energy?
(a) Coal
(b) Petroleum
(c) Water
(d) Natural gas

Question 2.
Which of the following is a non-renewable source of energy?
(a) Water
(b) Coal
(c) Soil
(d) Sun

Question 3.
Plastic is a
(a) natural material
(b) man-made material
(c) both (a) & (b)
(d) none of these

Question 4.
Fossil fuels are
(a) coal
(b) petroleum
(c) natural gas
(d) all of these

Question 5.
The word ‘coal’ is derived from the old English term
(a) col
(b) coke
(c) coco
(d) none of these

Question 6.
Which of the following minerals is present in coal?
(a) Hydrogen
(b) Oxygen
(c) Sulphur
(d) All of these

Question 7.
Naphthalene balls are used as
(a) mosquito repellant
(b) moth repellant
(c) snake repellant
(d) bee repellant

Question 8.
How much percentage of carbon is present in bituminous?
(a) 20 – 25%
(b) 25 – 35%
(c) 65 – 85%
(d) 98%
Question 9.
The process of conversion of wood into coal is called
(a) carbonisation
(b) catagenesis
(c) carboniferous
(d) none of these

Question 10.
Petroleum is also known as
(a)coke
(b) black gold
(c) tar
(d) none of these

Question 11.
The brown variety of coal is
(a) lignite
(b) peat
(c) anthracite
(d) none of these

Question 12.
The major constituent of natural gas is/are
(a) butane
(b) methane
(c) hydrogen
(d) ethane

Question 13.
The product obtained by destructive distillation of coal is
(a) coal tar
(b) coke
(c) coal gas
(d) all of these

Question 14.
The petroleum product which is not used as fuel is
(a) petrol
(b) kerosene
(c) diesel
(d) petroleum jelly

Question 15.
Main constituent of LPG is
(a) methane
(b) butane
(c) ethane
(d) propane

Question 16.
A natural gas stored under high pressure is called
(a) CNG
(b) LPG
(c) KLG
(d) PNP
Question 17.
Name the petroleum product used for surfacing of road.
(a) Peat
(b) Bitumen
(c) Lignite
(d) Anthracite

Question 18.
The mining of oil under sea is termed as
(a) distillation
(b) carbonisation
(c) shore mining
(d) destructive distillation

Question 19.
Which is the best type of coal?
(a) Lignite
(b) Anthracite
(c) Bituminous
(d) peat

Question 20.
Petroleum is separated by using the difference in
(a) ignition temperatures
(b) melting points
(c) freezing points
(d) boiling points
Answer:
1. (c)
2. (b)
3. (b)
4. (d)
5. (a)
6. (d)
7. (b)
8. (c)
9. (a)
10. (b)
11. (a)
12. (b)
13. (d)
14. (d)
15. (b)
16. (a)
17. (b)
18. (c)
19. (b)
20. (d)

II. Fill in the Blanks

Fill in the blanks with suitable word/s.
1. Resources which get replenished by natural processes in a certain period of time is called ___________.
2. ___________ is a mixture of various constituents such as lubricating oil, paraffin wax, etc.
3. ll the things that are required to fulfil one’s need are called ___________.
4. Anything that burns to produce energy is called a ___________.
5. ___________ is a black-coloured hard substance that mainly contains carbon.
6. The time period taken to complete the process of carbonisation is called ___________.
7. ___________ is the most inferior and softest form of coal.
8. The least polluting fuel for vehicle is ___________.
9. The major fossil fuels are ___________ and ___________.
10. The major component of CNG is ___________.
11. Destructive distillation of coal is done at ___________.
12. Petroleum is a mixture of different ___________.
13. ___________ is another name for petroleum.
14. Devices that consume less energy are ___________ and ___________ lights.
15. Forests are ___________ natural resources.
16. Petra means ___________ and oleum means ___________.
17. ___________ is the leading producer of crude oil.
18. When heated in air, coal burns and produces mainly ___________ gas.
19. We should use ___________ instead of individual vehicles.
20. Separation of different constituents of petroleum is called ___________.
Answer:
1. renewable resources
2. Petroleum
3. resources
4. fuel
5. Coal
6. carboniferous age
7. Peat
8. CNG
9. coal, petroleum
10. methane
11. 1000°C
12. hydrocarbons
13. Black gold
14. CFL, LED
15. exhaustible
16. rock, oil
17. Saudi Arabia
18. carbon dioxide
19. carpools
20. refining of petroleum

III. Match the following

Match the items given in column I suitably with those given in column II.
Answer:
1. (c)
2. (a)
3. (b)
4. (f)
5. (g)
6. (d)
7. (e)
8. (h)
9. (j)
10. (i)

IV. True or False

State whether the given statements are true or false.
1. Coal is a renewable source of energy.
2. Coal is a solid fossil fuel.
3. Coke is almost a pure form of carbon.
4. CNG is more polluting than petrol.
5. 40% of electricity generation depends on coal.
6. Carbon content of lignite is 25-35%.
7. Fossil fuels are inexhaustible natural resources.
8. We get napthalene ball from coal tar.
9. The time period take to complete carbonisation is called carboniferous age.
10. Peat is the hardest grade coal.
11. Petroleum is also known as ‘black gold.’
12. 30% of paraffins is present in petroleum.
13. Petroleum can be mixed with water.
14. Natural gas is transported through pipelines.
15. Kerosene is not a fossil fuel.
Answer:
1. False
2. True
3. True
4. False
5. True
6. True
7. False
8. True
9. True
10. False
11. True
12. True
13. False
14. True
15. False
Very Short Answer Questions

1. Write the names of two natural substances.

Answer: (i) Air (ii) Water

2. Name two man-made substances.

Answer: (i) Car (ii) Bus

3. Name two natural resources.

Answer: (i) Air (ii) Water

4. Write two exhaustible substances.

Answer: (i) Coal (ii) Natural gas

5. Why are air, water and soil called natural resources?

Answer: Air, water and soil are provided by nature so they are called natural resources.

6. Name any two inexhaustible natural resources.

Answer: (i) Air (ii) Sunlight

7. Why are Coal, Petroleum and Natural gas called fossil fuels?
Answer: Coal, Petroleum and Natural gas are formed by fossils, so they are called fossil fuels.

8. Which gas is produced when coal burns in air?

Answer: Carbon dioxide.

9. Name the gas which is formed when coal is heated in the absence of air.
Answer: Coal gas.

10. What is the purest form of carbon?

Answer: Coke.

11. What is the main use of coke?

Answer: It is used in the extraction of metals.

12. How many substances are found in coal tar?

Answer: About 200 substances.

13. Name the substance obtained from the coal tar and used to repel moths and insects.
Answer: Naphthalene balls.

14. Which substance is used for road surfacing these days?

Answer: These days bitumen is used for road surfacing in place of coal tar.

15. Where was the first oil well drilled?

Answer: The first oil well was drilled at Pennsylvania, USA, in 1859.

16. Where and when was the first oil well drilled in India?
Answer: In 1867, at Makum in Assam.

17. Name two fractions of petroleum which are used as fuel.

Answer: (i) Petrol (ii) Diesel

18. What are Petrochemicals?

Answer: The useful substances formed from natural gas and petroleum are called petro- chemicals.

19. Why is petroleum called black gold?

Answer: Due to its great commercial importance, petroleum is also called black gold.

20. Name the places where natural gas is found in our country.
Answer: Tripura, Rajasthan, Maharashtra and in the Krishna Godavari delta.
21. Expand PCRA.
Answer: Petroleum Conservation Research Association.

22. Can we use all our natural resources forever?

Answer: No, we cannot use all our natural resources forever, because these are going to exhaust one day.

23. Can air, water and soil be exhausted by human activities?

Answer: No, these cannot be exhausted at all.

24. Is water a limitless source?

Answer: Yes, water is a limitless source, but by unwise use and cutting of trees, sources of water can be finished.

Short Answer Type Questions

1: What is Inexhaustible Natural Resource?

Answer: The resources which are present in unlimited quantity in nature and are not likely to be exhausted by
human activities are known as Inexhaustible Resources. For Example: Sunlight, air

2: Define Exhaustible resources with few examples.

Answer: All resources which are found in a limited quantity in nature are known as Exhaustible resources. They can
be exhausted by human activities. Example of these resources is Forests, Minerals, Coal, Petroleum, Naturals Gas etc.

3: How was Coal formed?

Answer: About 300 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. They get sank deeper and deeper and temperature gets increasing
day by day, under high pressure and high temperature dead plants slowly got converted to coal.

4: How was Petroleum 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 in absence of air and under
high temperature and high pressure the dead organisms get transformed into Petroleum and natural Gas.

5: What do you mean by refining and petroleum refinery?

Answer: The process of separating various components or fraction of petroleum is called refining. This process is
carried out in petroleum refinery.

6: What do you understand by Petrochemical products. What are their uses?

Answer: Petroleum and natural gas provide many useful substances. These are termed as ‘Petrochemicals’. These are
used in manufacturing of detergents, fibres, polythene and other man made plastics

7: Name various constituents of Petroleum and their uses.

Answer: Products obtained by refining of petroleum are petroleum gas, petrol, diesel, kerosene, paraffin wax and
lubricating oil.

Constituents of Petroleum Uses

Petroleum Gas in Liquid form Fuel for home and Industry

Petrol Motor fuel, Aviation fuel, solvent for dry cleaning

Kerosene Fuel for stoves, lamps and for jet aircrafts

 Diesel Fuel for heavy motor vehicles, electric generators

Lubricating oil Lubrication

Paraffin wax ointments, candles, Vaseline etc.

Bitumen Paints, Road surfacing

8: Name few places where Natural Gas has been found in India.

Answer: In our country Natural Gas has been found in Tripura, Rajasthan, and Maharashtra and in the Krishna
Godavari Delta.

9: Why should we use some resources like coal and petroleum in limit?

Answer: As we know Coal and petroleum are fossil fuels. The dead organisms takes millions of years to get converted
into these fuels, On the other hand the known reserves of these will last almost a few hundred years. A part from this
since these products are not environmental friendly as burning of these fuels is a major cause of air pollution and
their use is also linked to global warming therefore we should use these resources only when it is actually required.

10: What are the advices of PCRA to save petrol/diesel while driving?

Answer:

1. Drive at a constant and moderate speed as far as possible

2. Switch off the engine at traffic lights or at a place where you have to wait

3. Ensure correct type pressure

4. Ensure regular maintenance of the vehicle.

11: What are the harmful effects of using fossil fuels?

Answer: Harmful effects of burning fossil fuels are as following:

(i) Burning of fossil fuels cause air pollution.
(ii) They also cause global warming because they produce greenhouse gas like carbon dioxide on burning.

12: What does CNG stand for and what are the benefits of using CNG as fuels?

Answer: CNG stands for Compressed Natural gas. In CNG compressed gas (which is mainly methane gas) is stored
under high pressure as compressed natural Gas.
Advantages of CNG:

 CNG is a very important fossil fuel because it is easy to transport through pipes.

 It is a cleaner fuel.

 CNG-powered vehicles have lower maintenance costs when compared with other fossil fuel-powered
vehicles.

 CNG fuel systems are sealed, which prevents any spill or evaporation losses.

 CNG mixes easily and evenly in air being a gaseous fuel.

13: What does LPG Stand for and its uses?

Answer: LPG stands for “Liquefied Petroleum Gas”, it is used as fuel for home and industry as it is less polluting and
easy to transport and to use.
14: Why Coal is called Fossil fuel?

Answer: Coal is called Fossil fuel because it is made up of remains of dead animals and dead plants which also
formed fossils.

15: Why the layer containing petroleum and Gas is above the water?

Answer: The layer containing petroleum and Gas is above water because oil and Gas are lighter than water and can’t
get mix with it.

16: Why Coal, Petroleum and Natural Gas can’t be prepared in Laboratory?

Answer: These natural resources can’t be prepared in laboratory because their formation is a very slow process and
it is not possible to create the conditions for their formation in the laboratory.

17: Explain the uses of coal.

Answer: Coal’s primary use is for the generation of electricity. It is also used in the industrial and retail sector as fuel
for heating and powering foundries, cement plants and other industrial and manufacturing facilities.

18: What is the main reason for coal to be used to generate electricity?

Answer: Coal is used to generate the electricity because it is reliable and low cost energy source.

19: Explain few advantages and disadvantages of using petroleum.

Answer: Few advantage of using Petroleum as fuel and as raw materials are:

 Storage and transportation are simple

 Spills and leaks are controllable using existing technology

 As raw material in chemical synthesis it is extremely flexible

Disadvantages:

 Over use can create local and global problems

 It is limited resource which can be used up by wasteful procedures

20: What could be the potential risk using oil as fuel or source of energy?

Answer: Burning oil for energy can release large amounts of carbon dioxide, which can contribute to global warming.
In addition the risk of dependence on oil as energy source is that supplies are eventually going to be depleted.

21: Why is Petroleum known as Black gold?

Answer: Petroleum and its products are very important for us, and because of its great commercial importance, it is
named as “Black gold”

22: Name the material by which Plastics are made?

Answer: Petroleum.

23: What is Coal gas?

Answer: Coal gas is obtained during the processing of Coal to get coke. It is used as a fuel in many industries situated
near the coal processing plants.

24: What is PCRA?

Answer: PCRA stands for Petroleum Conservation Research Association, it advices people how to save petrol and
diesel while driving by giving following tips:

 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

 Ensure regular maintenance of the vehicle

25: How burning of fossil fuels causes air pollution?

Answer: Pollutants that come from the combustion of fossil fuels include sulphur dioxide (SO2), nitrogen oxides,
ground-level ozone, particulate matter (PM), carbon monoxide (CO), carbon dioxide (CO2), volatile organic
compounds (VOC) including benzene, some heavy metals and a number of other pollutants which contribute to
smog, acid rain, climate change, and health, environmental and economic concerns.

26: What are natural resources? Explain with examples.

Answer: The resources provided by nature or obtained from the nature are called natural resources. For example: air,
water, soil and sunlight etc.

27: Classify the natural resources on the basis of their availability.

Answer: On the basis of the availability various, natural resources in nature can be classified in the following two
groups:
(i) Inexhaustible natural resources: Air, Water, Soil, Sunlight, etc.
(ii) Exhaustible natural resources: Forests, Wildlife, Minerals and Coal etc.

28: What are fossil fuels? Name the main fossil fuels.

Answer: The remains of dead plants and animals are called fossils. The fuels formed by the remains of dead plants
and animals are called fossil fuels. Main fossil fuels are: coal petroleum and natural gas.

29: What is coke? Write its uses.

Answer: Coke is a tough porous and black substance. It is almost the purest form of carbon. It is formed by heating
coal in the absence of air.

Uses:
(i) It is used in manufacture of steel.
(ii) It is used in the extraction of metals.

30: What is coal tar? What are its uses?

Answer: Coal tar is a black thick liquid. It is a mixture of about 200 substances.
Uses:
(i) It is used as a source of various useful substances.
(ii) It is used to get naphthalene which is used to repel moths and other insects.
(iii) It is used to make road surface.

31: What is coal gas? Write the uses of coal gas.

Answer: Coal gas is a by-product formed when coal is heated in absence of air.
Uses:
(i) It is used as fuel in many industries.
(ii) Previously it was used for street lighting in London in 1810.

32: What is petroleum? Why is it called black gold?

Answer: Petroleum is a dark oily liquid. It is a mixture of various constituents. Its constituents are very useful. Due to
its great commercial importance petroleum is also called black gold.

33: Where and when was the first oil well drilled? (i) in world and (ii) in India.
Answer: (i) The world’s first oil well was drilled in Pennsylvania, (U.S.A.), in 1859.
(ii) In India, the first oil well was drilled at Makum (Assam) in 1867.

34: Why is natural gas called a very important fossil fuel in these days?

Answer: Natural gas is a very important fossil fuel because it is easy to transport through pipes. It is used in the form
of CNG as fuel and generation of power.

35: Why is CNG called a clean fuel?

Answer: CNG is called a clean fuel because:

(i) It does not produce any pollution.
(ii) No residue is left after burning of CNG.
(iii) It burns completely in the air.

Long Answer Type Questions

1: Discuss importance of natural gas in our daily life.

Answer: Natural gas is very important fossil fuel as it is very easy to transport through pipes, apart from this also it
can be stored under high pressure as compressed natural gas (CNG) which is being used now a day as a fuel for
transport vehicle.
CNG stands for Compressed Natural gas. In CNG compressed gas (which is mainly methane gas) is stored under high
pressure as compressed natural Gas.
Advantages of CNG:

 CNG is a very important fossil fuel because it is easy to transport through pipes.

 CNG is also used for power generation and now used as fuel for transport vehicles because it is less polluting.

 It is a cleaner fuel.

 CNG-powered vehicles have lower maintenance costs when compared with other fossil fuel-powered
vehicles.

 CNG fuel systems are sealed, which prevents any spill or evaporation losses.

 Natural gas is also used as starting material for the manufacture of a number of chemicals and fertilisers.

2: Explain fossil fuels.

Answer: Some exhaustible natural resources like coal, petroleum and natural gas are called fossil fuels as they are
formed from the dead remains of living organisms (fossils). Fossil fuels are non-renewable resources because they
take millions of years to form, and reserves are being depleted much faster than new ones are being made. The
production and use of fossil fuels raise environmental concerns.

Coal: About 300 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. They get sank deeper and deeper and temperature gets increasing
day by day, under high pressure and high temperature dead plants slowly got converted to coal. Coal’s primary use is
for the generation of electricity. It is also used in the industrial and retail sector as fuel for heating and powering
foundries, cement plants and other industrial and manufacturing facilities.

Petroleum: 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 in absence of air and under
high temperature and high pressure the dead organisms get transformed into Petroleum and natural Gas. Petroleum
is a dark oily liquid. It has an unpleasant odour. It is a mixture of various constituents such as Petrol, Diesel, etc. and
the process of separating these constituents from crude oil is called Refining.

3: Describe coal and its various products along with their uses.
Answer: Coal is a hard and black coloured non-metal which is used to cook food, in the past it was also used to run
railway engines, apart from this it is also used to produce electricity in thermal power plant; it is also used as fuel in
various industries.

Following are the products of coal:

1. Coke: Coke is a product of coal; it is tough, porous, and black in colour and almost pure form of carbon. It is used in
making steels and in extraction of many metals
2. Coal tar: coal tar is the product of coal which is the mixture of various substances. Products obtained from coal tar
is used for manufacturing a variety of products like dyes, drugs, perfumes, explosives, paints, photographic materials,
roofing materials etc.
3. Coal gas: Coal gas is obtained during the processing of Coal to get coke. It is used as a fuel in many industries
situated near the coal processing plants.

4: Write notes on wide and judicious use of our exhaustible natural resource.

Answer: Exhaustible resources like coal, petroleum are formed from the dead organisms, it takes millions of years for
formation of these fuels, and On the other hand the known reserves of these will last almost a few hundred years. A
part from this since these products are not environmental friendly as burning of these fuels is a major cause of air
pollution and their use is also linked to global warming therefore we should use these resources only when it is
actually required. Wise use of natural resource will result in better environment, smaller risk of global warming and
their availability for a longer period of time.

5: Write the names of various components of petroleum and write their uses.

Answer: The petroleum is the mixture of various fractions. These fractions are separated by the process of refining:
We get following fractions by the process of refining:

(1) LPG (Liquefied Petroleum Gas):

Uses: It is used as domestic and industrial fuel.

(2) Petrol
Uses: It is used as motor fuel, aviation fuel and solvent for drycleaning.

(3) Kerosene
Uses: It is used as fuel for stoves, lamps and for jet aircraft.

(4) Diesel
Uses: It is used as fuel for heavy motor vehicles and electric generators.

(5) Lubricating Oil

Uses: It is used as a lubricant.

(6) Paraffin Wax

Uses: It is used in making ointments, candles and vaseline etc.

(7) Bitumen
Uses: It is used in making paints and road surfacing.

6: What advise is given by PCRA for saving petrol and diesel?

Answer: The advise given by PCRA are as following:

(i) Drive at a constant and moderate speed as far as possible.
(ii) Switch off the engine at traffic lights or at a place where you have to wait.
(iii) Ensure correct tyre pressure.
(iv) Ensure regular maintenance of the vehicle.
If we follow the tips given by PCRA, then we can save more and more petrol or diesel. In this way we can save money
and energy of the nation.