NCERT Exemplar Solution Class 8 Science Chapter 5
NCERT Exemplar Solution Class 8 Science Chapter 5 Coal and petroleum all Questions Answer Solution. NCERT Exemplar Class 8 Science Chapter 5 Solution PDF.
NCERT Exemplar Solution Class 8 Science Chapter 5: Overview
NCERT Exemplar Solution Class 8 Science Chapter 5 |
|
Board |
NCERT |
Topic |
Exemplar Problem Solution |
Class |
8 |
Subject |
Science |
Chapter |
5 |
Chapter Name |
Coal and petroleum |
NCERT Exemplar Solution Class 8 Science Chapter 5 Coal and petroleum
Multiple Choice Questions
1) Various materials which are obtained from nature are called natural resources. Which of the following is not a natural resources?
a) Minerals
b) Water
c) Soil
d) Plastic
Answer:- d) Plastic
Plastic is a synthetic polymer. It is not a national resource. While the other minerals, soil and water are naturally available in the environment.
2) Air is a natural resource and cannot be exhausted by human activities. It is known as inexhaustible natural resource. Which of the following is another inexhaustible natural resource?
a) Coal
b) Petroleum
c) Sun-light
d) Minerals
Answer:- c) Sun-light
Coal, petroleum and minerals are exhaustible resources. I.e. they are limited in the nature. But sunlight is inexhaustible. It is unlimited.
3) Which of the following is a pair of exhaustible natural resources.
a) Coal and soil
b) Water and petroleum
c) Air and sun- light
d) Wild life and minerals
Answer:- d) Wild life and minerals
Wild life and minerals both are exhaustible natural resources. Other pairs contains exhaustible and inexhaustible resource both.
4) Coal is processed in industries to get some useful products. Which of the following is not obtained from coal?
a) Coke
b) Coal gas
c) Coal tar
d) CNG
Answer:- d) CNG
CNG is compressed natural gas which is obtained from the dead organisms remains under the sea. Coke, coal gas and coal tar are obtained from coal.
5) 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
The resources which are present in limited quantity in nature and can be finished by the human activity are called as exhaustible natural resources.
6) 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.
Fossil fuels are obtained from The dead remains of all the living organisms.
7) Coal is formed from the remains of
a) Vegetation only
b) Both vegetation and animals
c) Animals only
d) Neither vegetation nor animals
Answer:- a) vegetation only
Coal is also known as Fossil fuels. It is formed from the buried vegetation from the several years.
8) Which substance is formed by the carbonisation of dead vegetation?
a) Coal
b) Coke
c) Coal gas
d) Coal tar
Answer:- a) Coal
Carbonation is slow and steady process of dead vegetation into coal. It takes several years.
9) Naphthalene balls are obtained from coal tar and are used as
a) Mosquito repellent
b) Honey bee repellent
c) Moth repellent
d) Snake repellent
Answer:- c) Moth repellent
Coal tar is a mixture of about 200 substances. Naphthalene is also manufacture from the coal tar and it is used to repel moth and other insects.
10) Which of the following is not a constituent of petroleum?
a) Paraffin wax
b) Lubricating oil
c) Petrol
d) Coke
Answer:- d) Coke
Coke is an product of coal. It is produced in the factories after processing coal. Other are the products of petroleum.
11) 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
Petroleum is found under the sea. It is formed from organisms living in the sea.
Dead sea organisms after several years convert into Petroleum and natural gas.
12) Choose the correct 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:- c) Natural Gas is stored under high pressure as compressed natural gas.
Natural gas is obtained from the sea, under high pressure. It is removed and stored under high pressure. It is also known as CNG i.e. compressed natural gas.
Very Short Answer Questions
13) You are provided with a mixture of petroleum and water. Can you suggest a method to separate the two?
Answer:- yes. We can separate the two mixture of the petroleum and water using the process of decantation.
Petroleum substances float over the water, which can be easily separate from water by removing a upper layer of petroleum along with some water. Thus both will be separated.
Fig showing the process of decantation
14) What does CNG stand for and why is it considered to be a better fuel than petrol?
Answer:- Compressed Natural Gas is known as CNG. It is a natural gas which is obtained from the dead organisms of the sea. It is formed from the dead of organisms remains under high pressure, without air in the water. These gas is stored under high pressure. Therefore it is known as compressed gas. It is easier to transport it through the pipes. CNG is also now using in vehicles as it is less polluting.
15) Name the petroleum product used as fuel for stoves, lamps and jet aircrafts.
Answer:- The petroleum product known as kerosene is used as a fuel in stoves, lamps and jet aircrafts.
16) Fill in the blanks in the following sentences.
a) Coal is one of the ___________ used to cook food.
Answer:- Coal is one of the fuels used to cook food.
b) When heated in air, coal burns and produces mainly __________ gas.
Answer:- when heated in air, coal burns and produces mainly carbon dioxide gas.
c) Coal tar is a Black, thick , ________ with an ____________ smell.
Answer:- Coal tar is a black, thick, liquid with an unpleasant smell.
d) Petroleum , _____________ and _____________ are Fossil fuels.
Answer:- petroleum, coal and natural gas are Fossil fuels.
e) Forests and coal are ____________ natural resources.
Answer:- Forests and coal are exhaustible natural resources.
17) The underlined words in the following sentences have been have jumbled up. Write in their correct form.
a) Loca is obtained from mines.
Answer:- Coal is obtained from mines.
b) Umpetloreis a fossil fuel.
Answer:- is a Fossil fuel.
c) Rineryfe is a place where various fractions of petroleum are separated.
Answer:- Refinery is a place various fractions of petroleum are separated.
d) Keenrose is a fuel used in jet crafts.
Answer:- Kerosene is a fuel used in jet crafts.
e) Nutsgilh is an example of inexhaustible natural resources.
Answer:- Sun-light is an example of inexhaustible natural resources.
18) Fill in the blanks.
a)The slow process of conversion of dead vegetation into coal is called _____________.
Answer:- 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 ______________.
Answer:- Coal and petroleum are formed from the dead remains of organisms and are known as Fossil fuels.
c) The blank thick liquid with __________ smell is known as coal tar.
Answer:- The blank thick liquid with unpleasant smell is known as coal tar.
d) During the processing of coal to get coke, coal tar and _________ are also obtained.
Answer:- During the processing of coal to get coke, Coal tar and Coal gas are also obtained.
e) The process of separating the various constituents of petroleum is known as ____________.
Answer:- The process of separating the various constituents of petroleum is known as Refining.
f) Excessive burning of fossil fuels is a major cause of ___________.
Answer:- Expression burning of fossil fuels is a major cause of air Pollution.
19) Write True/ False against the following statements.
a) Oxygen in air is an exhaustible natural resource.
Answer:- FALSE
Oxygen in air is inexhaustible natural resource.
b) Resources which are present in unlimited quantity in nature are called exhaustible natural resources.
Answer:- FALSE
Resources which are present in limited quantity in nature are called exhaustible natural resources.
c) Wildlife is an exhaustible natural resource.
Answer:- TRUE
d) Under high temperature and pressure, dead plants get slowly converted to coal.
Answer:- TRUE
e) CNG is less polluting fuel than petrol and diesel.
Answer:- TRUE
Short Answer Questions
20) Sunlight and air are inexhaustible natural resources. Comment.
Answer:- Inexhaustible is an term used for the substances which are in unlimited quantity nature. Sunlight and air is available in unlimited quantity in nature. And it will not be used up all by the human activity. Therefore these are inexhaustible natural resources.
21) Some natural resources are given in a box. Classify them into the exhaustible and inexhaustible natural resources.
Air, coal, natural gas, sun-light, petroleum, minerals, forests , oxygen.
Answer:- these are classified as below
Exhaustible natural resources :- coal, natural gas, petroleum, minerals, forests.
Inexhaustible natural resources:- air, sunlight, Oxygen.
22) Write two important uses of coke.
Answer:- Coke is a tough, black substance and porous. It is produced from the coal after processing in industry. It is used in the manufacturing steel and also it is used in the extraction of many metals.
23) Write the characteristics and some important uses of coal.
Answer:- Coal is a fossil fuel which is obtained from the dead vegetation. Vegetation buried under the deep layers of earth for the several years, and converted into coal by the process of carbonation. These call is hard as stone and dark black in colour.
It is used as a fuel to cook food.
It is used in railway engines as a fuel to produce steam for running engine.
It is also used as fuel in the thermal power plants for producing electricity.
It is also used in industries for manufacturing other useful products.
Coal is processed to form coke, coal tar , and coal gas.
24) Look at fig. 5.1 where petroleum and natural gas deposits are shown. Why do we find oil layer above water layer?
Fig. 5.1
Answer:- In the fig. 5.1. it is shown that petroleum and natural gas are deposited above the water surface. These is due to gas and oil are lighter than the water. And these do not with each other. Therefore it floats over the water surface.
25) 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 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 into coal.
26) 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:-
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
27) Name the products obtained and their uses when coal is processed in industry.
Answer:-
Coal is a fossil fuel which is obtained from the dead vegetation buried from several years under the earth.
Coal is processed in the industries to obtained some products, the products and their uses are as below:-
1) Coke :-
Coke is tough, black coloured substance, and porous in nature.
It is used to manufacture steel and extract some other metals.
2) Coal tar :-
Coal tar is also obtained from processing coal. It is thick, black coloured liquid with unpleasant smell. Coal tar is used as starting material of many day to day life useful products.
It is processed in industries to form-
Drugs
Synthetic dyes
Photographic materials
Naphthalene balls
Perfumes
Plastic
Roofing materials
Explosives
3) Coal gas :-
Coal gas is obtained during the process of getting coke from coal.
It is used as fuel in many industries which are present near the coal processing industries.
28) We say fossil fuels will last only for a few hundred years. Comment.
Answer:- Fossil fuels are exhaustible natural resources. These are formed after several hundred years when dead living organisms or dead vegetation are buried under earth. It takes a long duration of time to form. Formation of fossil fuels needs a specific condition. And these conditions doesn’t happen often. Therefore fossil fuels are exhaustible and limited in quantity. They can be finished early due to uses of human beings.
29) We read in newspapers that burning of fuels is a major cause of global warming. Explain why.
Answer:-
Burning of fossil fuels release dangerous gases in the atmosphere which increases the temperature of the earth. And these is responsible for the global warming. Burning of fossil fuels release Carbon dioxide gas more in quantity which is mainly responsible for the global warming.
30) While driving what are the tips we must follow to save petrol/ diesel/ natural gas ?
Answer:- petrol /diesel/ natural gas are exhaustible natural resources. These are limited in quantity. These natural resources can be exhausted early. Therefore we should use it carefully. For saving these resources we can take following precautions-
Switch off engine at the traffic lights.
Switch off engine when the vehicle is stopped somewhere
Drive at slow speed and constant speed.
We should ensure the correct pressure of tyre regularly.
We should maintain the vehicle.
31) Imagine that all the exhaustible natural resources are exhausted by human activities. Do you think survival of living beings would be possible? If yes, why? If not, why not?
Answer:- No. I think, survival of living beings without natural resources is not possible. These natural resources are very much important for day to day life in human beings. We have find out these resources and used it in production of many useful things. Now we are dependent over the things which are getting from the natural resources. We are using many products in our day to day life which we are processing from the exhaustible natural resources such as coal, petroleum products, metals, natural gas etc. We cannot live without these products in current situation of world. Yes, it was possible before several hundred years ago, when human beings were living in the ancient time. But now we can’t.
32) Why petrol is exhaustible natural resources, whereas sunlight is not? Explain.
Answer:-
we get sunlight form the sun. Sun is at its fixed position and gives daily sun-light which is inexhaustible. It cannot uses up totally as it is not in limited quantity. It is unlimited. Therefore it will not finished by human beings. Whereas petrol is obtained from the exhaustible natural resource which is petroleum. Petroleum is obtained from the sea. Which is further processed to get the various products along with petrol. These petroleum is obtained from the dead organisms under the sea, these is formed after several years when dead animals are settled down in the sea, under tremendous pressure, without air. Therefore it is in limited quantity.
33) Write some important uses of the various constituents of petroleum.
Answer:-
Some important uses of the various forms of Petroleum are as below-
1) Petrol:- petrol is used as fuel in vehicles and aviation.
2) Kerosene:- it is used as fuel in the jet aircraft, stoves and lamps.
3) Diesel :- diesel is also used in the vehicle as fuel, and in Electric generators.
4) LPG:- these is the liquid form of petroleum gas which is used in day to day life for cooking at home.
5) Lubricating oils:- it is used for lubrication.
6) Bitumen:- this is used in the road Surfacing and in paints.
7) Paraffin wax:- it is used in the ointments, Vaseline, and candles etc.
34) Coal reserves are said to be enough to last for another hundred years. Do you think we need to worry in such ? Why or why not?
Answer:- I think if the coal is remained for another hundred years, then also we have to be careful about the use of the coal. As we know the population of the world is increasing. As per the population is increasing they will need more natural resources further for their use. Therefore we should carefully use the coal or other exhaustible natural resources . These will be helpful for future of human beings.
35) What steps would you suggest for the judicious use of fossil fuels?
Answer:-
For the judicious use of fossil fuels I will suggest the following points –
1) General awareness among the people for the minimum use of fossil fuels.
2) Fossil fuels like coal and wood should not be used for burning in houses.
3) Petroleum substances like petrol, diesel should be used carefully.
4) At the place of fossil fuels like petrol and diesel we should use Electric vehicles or use common vehicles.
36) Complete the crosswords fig. 5.2 with the help of the clues:
Fig. 5.2
Across :
1) Fuels obtained from dead remains of living organisms.(6,5)
2) A process by which the various constituents of petroleum are separated.(8)
3) A porous black substances obtained form coal. (4)
4) Another name of motor fuel.(6)
Down-
5) The substances obtained by carbonisation.(4)
6) Fuel for heavy motor vehicles.(6)
7) A petroleum product used for road Surfacing. (7)
8) Dead remains of sea animals
got converted into it. (9)
Answer:-