RBSE Solutions for Class 8 Science Chapter 18 Carbon and Fuel

Rajasthan Board RBSE Class 8 Science Chapter 18 Carbon and Fuel

RBSE Solutions for Class 8 Science

RBSE Solutions for Class 8 Science Chapter 18 Carbon and Fuel

RBSE Class 8 Science Carbon and Fuel Intext Questions and Answers

Page No 191.

Question 1.
Write the name of fuel used in front of given work in the following table –
Answer:
Table: Fuels Used in different work
RBSE Solutions for Class 8 Science Chapter 18 Carbon and Fuel-1

Page No 195.

Question 2.
When you cover up lighten candle with container, after sometime why the candle stop burning.
Answer:
When we cover up the lighten candle with container, it will burn till it gets proper amount of oxygen. As soon as the oxygen is finished then candle blew out.

Page No 196.

Question 3.
You might have heard that in summer season due to high temperature dry grass capture fire and even forests came under fire. Sometimes coal dust in coal mines starts burning automatically. Why it happens?
Answer:
Each and every thing is having the fixed approximate ignition temperature. At fixed temperature the things becomes warm and slowly-slowly start to burn in presence of oxygen. This is the reason that in summer dry grasses and coal dust automatically undergoes to combustion.

RBSE Class 8 Science Carbon and Fuel Text Book Questions and Answers

Choose the correct option:

Question 1.
The coal in which carbon content is highest –
(a) Peat
(b) Lignite
(c) Anthracite
(d) Bituminous
Answer:
(c) Anthracite

Question 2.
The residue of fractional distillation of petroleum is –
(a) Lubricant oil
(b) wax
(c) Coal tar
(d) Diesel
Answer:
(c) Coal tar

RBSE Solutions for Class 8 Science Chapter 18 Carbon and Fuel

Question 3.
The crystalline allotrope of carbon is –
(a) Coal
(b) Kajal
(c) Charcoal
(d) Graphite
Answer:
(d) Graphite

Fill in the blanks:

  1. ………………….. is the domestic liquid fuel.
  2. In graphite each carbon atom is attached to ………………….. nearest carbon atoms while in diamond each carbon atom is attached to nearest carbon atoms.
  3. ………………….. is necessary for combustion.

Answer:

  1. EPO
  2. three, four
  3. oxygen

Put right (I) for correct and wrong (K) for incorrect of the following:

  1. The carbon content in Lignite is 67%. ( )
  2. Peat coal is an example of liquid fuel. ( )
  3. Lubricant oil is used as fuel in vehicles and kitchen. ( )
  4. The crystalline allotropes of carbon are diamond, graphite and fullerin. ( )

Answer:

  1. True
  2. False
  3. False
  4. True

RBSE Solutions for Class 8 Science Chapter 18 Carbon and Fuel

Short answer type Questions:

Question 1.
Write uses of petroleum gas.
Answer:
Use of petroleum –

  1. It is mainly usable in vehicles and kitchens in the form of fuel.
  2. It has the mixture of ethane, propane, butane, isobutane. This mixture can be liquified petroleum gas (LPG), when it is filled up in cylinders. Its uses are increasing day by day in the form of domestic fuel. This gas gives up more heat in minimum time.
  3. It can he burn p easily and it does not produce ash.

Question 2.
We should sensibly use petrol and diesel like substances? Explain why?
Answer:

  1. Petroleum is a non-renewable energy source because it forms with long period process. There are limited stocks/mines of petroleum.
  2. Petroleum and diesel which are obtained from petroleum are increasing .atmospheric pollution.
  3. We should use the petroleum carefully. If we will use petrol-diesel mostly, then it is possible that stocks of petroleum will he wined up in future.

Question 3.
Write differences between diamond and graphite.
Answer:
RBSE Solutions for Class 8 Science Chapter 18 Carbon and Fuel-2

Question 4.
Compare LPG and Wood as fuel.
Answer:
LPG:

  1. It burns completely and no residue left.
  2. Its heat index is very high so we get more heat by burning LPG.
  3. No air pollution on burning.
  4. It contribute to forest conservation.

Wood:

  1. On burning it gives smoke in large amount which is harmful lo man.
  2. Comparatively its heal index is low and on burning to wood gives less heal.
  3. Air pollution develop.
  4. It becomes the cause of deforestation, which is harmful to environment.

RBSE Solutions for Class 8 Science Chapter 18 Carbon and Fuel

Question 5.
Name five compounds of carbon.
Answer:

  1. Wood
  2. Graphite
  3. Diamond
  4. Natural gas
  5. Diesel etc.

Long answer type Questions:

Question 1.
Draw a well labelled diagram of diamond and graphite and explain their difference.
(OR)
Draw a labelled diagram of crystalline allotropes of carbon (diamond and graphite) and write its two uses also.
Answer:
RBSE Solutions for Class 8 Science Chapter 18 Carbon and Fuel-4

Question 2.
Write your views in the following table and also discuss with other students.
Answer:
Advantage and disadvantage by the use of petroleum fuel
Advantages of uses of Petroleum as fuel:

  1. By use in vehicle of transport, convenient to carry good and passengers from one place to other.
  2. Use in factories and industries by this there is increase in production capacity.
  3. Use in domestic work/fuel helpful in work.
  4. These fuels are easily available.

Disadvantages of uses of Petroleum as Fuel:

  1. Due to smoke of vehicles air pollution increases.
  2. Due to emit of poisonous gas and liberation of liquid chemicals there is increase in the air and water pollution.
  3. Increase in air and water pollution.
  4. Stocks are limited. Due to unlimited use these stocked will exhausted.

Question 3.
The use of petrol, diesel and kerosene ¡s rising day to day. Their smoke is mixing with air and causing air pollution. Write your suggestions and views for reducing air pollution.
Answer:
Harmful effects of use of petrol, diesel and kerosene –

  1. There is incomplete combustion of petrol, diesel and kerosene, by which carbon monoxide gas formed. which is a poisonous gas. It works to reduce the oxygen carrying capacity in blood.
  2. Tetra ethyl lead found in leaded petrol is a injurious pollutant. It causes cancer and tuberculosis,

Protection –

  1. We should used unleaded petrol and CNG in vehicles.
  2. LPG should he used as domestic fuel.

RBSE Solutions for Class 8 Science Chapter 18 Carbon and Fuel

Question 4.
List the fuel used in daily life.
Answer:
In our daily routine we use following fuels for different purposes like domestic work vehicles / instrument. We can classify and listed in three stages –

1. Solid Fuel – Wood coal, hard coal, fuel of cow dung (cowdung cakes), wastage of agriculture, wood etc.
2. Liquid Fuel – Kerosene, diesel, petrol, gasoline, alcohol etc.
3. Gas Fuel – Gobar gas, water gas, coal gas, producer gas, natural gas, LPG etc. are the gaseous fuels.

Question 5.
Draw the diagram of extraction of petrol and label it.
Answer:
RBSE Solutions for Class 8 Science Chapter 18 Carbon and Fuel-5

Question 6.
Differentiate complete and incomplete combustion. Explain with example.
Answer:
Complete combustion:

  1. Bums up with blue flame is known as complete combustion.
  2. In this substance get proper amount of oxygen.
  3. Requires constant temperature.
  4. It does not give smoke.
  5. It does not produce pollution.
  6. It does not give lampblack.
  7. Example – Combustion of LPG

Incomplete combustion:

  1. Burns up with yellow flame is known as incomplete combustion.
  2. Does not get proper amount of oxygen.
  3. Does not requires constant temperature.
  4. Gives smoke.
  5. Produce pollution.
  6. Gives lampblack.
  7. Example – Combustion of wood.

RBSE Class 8 Science Carbon and Fuel Important Questions and Answers

Objective Questions:

Question 1.
The following is the example of crystalline allotropes –
(a) Graphite
(b) Diamond
(c) Fullerence
(d) All of the above
Answer:
(d) All of the above

Question 2.
The following is the example of Acrystalline allotropes –
(a) Animal charcoal
(b) Diamond
(c) Graphite
(d) Fullerence
Answer:
(a) Animal charcoal

RBSE Solutions for Class 8 Science Chapter 18 Carbon and Fuel

Question 3.
Graphite is the conductor of electricity.
(a) Bad conductor
(b) Good conductor
(c) Very less conductor
(d) None of the above
Answer:
(b) Good conductor

Question 4.
Following is the formula of methane –
(a) CH3
(b) CH2
(c) CH4
(d) CH
Answer:
(c) CH4

Question 5.
From following the essentially for combustion
(a) Oxygen
(b) Constant temperature
(c) Fuel
(d) All of the above
Answer:
(d) All of the above

Fill in the blanks:

  1. Carbon is found in ……………………… and ……………………… both condition. (free, combined / not, free, uncombined)
  2. In houses mostly ……………………… gas is used. (LPG / CNG)
  3. Carbon is having crystalline and ……………………… both forms. (acrystalline / allotropes)
  4. The main cause of combustion of fuel is ……………………… (temperature / air pollution)
  5. Refinement of petroleum is done by the ……………………… process. (fractional distillation / non-fractional distillation)

Answer:

  1. free, combined
  2. LPG
  3. acrystalline
  4. air pollution
  5. fractional distillation.

Match the Column –

Question 1.
Match the following correctly:
RBSE Solutions for Class 8 Science Chapter 18 Carbon and Fuel-6
Answer:

  1. (C)
  2. (A)
  3. (D)
  4. (E)
  5. (B)

Very Short Answer Type Questions:

Question 1.
How the one form of carbon slippery material lampblack is obtained?
Answer:
We obtained by incomplete combustion of oil.

Question 2.
Till now how many elements approximately we know?
Answer:
Up to now we know approximate 118 elements.

Question 3.
Write the number of elements obtained from nature.
Answer:
The number of obtained clement from nature is 92.

Question 4.
In what form carbon is present in non – living materials?
Answer:
Carbon is present in free and combined, both forms in non-living materials.

RBSE Solutions for Class 8 Science Chapter 18 Carbon and Fuel

Question 5.
Write the name of carbon containing materials found in nature.
Answer:
Sugar, glucose, tea, milk, coal, petrol, diesel, natural gas. kerosene, diamond, graphite, etc. in all carbon is present.

Question 6.
Write the example of free state of carbon.
Answer:
Coal. lampblack, graphite, diamond and the examples of carbon’s free state.

Question 7.
In what form the carbon is present in most of the fuels?
Answer:
In most of the fuels the carbon is present in form of carbon compound or clement.

Question 8.
Which types of fuels used in cooking food?
Answer:
In our daily life LPG, wood, biogas, wood coal, hard coal, etc. are used in cooking food.

Question 9.
What is biomass? Give example.
Answer:
The material present in the body of plants and animals is called biomass. Example – wood, agriculture waste, dung etc.

Question 10.
What is carbonification?
Answer:
Slow process of dead plants in coal alteration is known as carbonification,

Question 11.
What is meant by fossil fuel?
Answer:
In coal mainly carbon is present and it is formed from remains of plants. so ii is a type of fossil fuel.

Question 12.
How the petroleum is refined?
Answer:
Refinement of petroleum is done by the fractional distillation process.

Question 13.
Why petroleum is called mineral oil?
Answer:
Petroleum is found in inner layer of rocks of earth. So due to this reason it is called mineral oil.

RBSE Solutions for Class 8 Science Chapter 18 Carbon and Fuel

Question 14.
Which is liquid gold and why we say?
Answer:
Petroleum is called liquid gold. In the present days, petroleum is more valuable than gold for any country. because any country’s success depends on the quantity of petrol it has.

Question 15.
Write the essential component for combustion of materials.
Answer:
For combustion of any substance, there are three components are essential –

  1. Air (oxygen)
  2. constant temperature
  3. fuel.

Question 16.
What is obtained firstly in fractional distillation of petroleum?
Answer:
In fractional distillation of petroleum firstly separation of petroleum gas takes place at temperature 25°C to 30°C.

Question 17.
What is meant by ignition temperature?
Answer:
The temperature at which any substance start to burn, that temperature is known as ignition temperanire of that substance.

Short Answer Type Questions:

Question 1.
Increasing percentage of carbon in coal increases is qualities. What are the kinds of coal on the basis of carbon Quantity?
Answer:
In the basis of carbon quantity in coal, coal is mainly divided into following four parts –

  1. Peat (60 percent)
  2. Lignite (67 percent)
  3. Bitumen (80 percent)
  4. Anthracite (90-98 percent).

RBSE Solutions for Class 8 Science Chapter 18 Carbon and Fuel

Question 2.
What is meant by allotropes and allotropy?
Answer:
When any element exists in two or more forms, whose physical properties are different but chemical properties remain same called allotropes. This type of quality of the element is called as allotropy.

Question 3.
Write in brief about allotropes of carbon.
Answer:
There are two types of allotropes of carbon –
1. Crystal line Allotropes –
Those allotropes which have certain geometry and structure of carbon atoms are known as crystalline allotropes of carbon, example graphite, diamond, fullerence, etc.

2. Acrystalline Allotropes –
Those allotropes which do not have certain geometry and structure of carbon atoms are known as acrystalline allotropes of carbon. Example – wood coal, lampblack. etc.

Question 4.
Demonstrate by chart the allotropes of carbon.
Answer:
RBSE Solutions for Class 8 Science Chapter 18 Carbon and Fuel-7

Question 5.
Classify the fuels on the basis of three states of matter.
Answer:

  1. Solid Fuel – Wooden coal, stone or hard coal, cow dung (cowdung cakes), wood, agriculture waste, etc. are comes in the category of solid fuel.
  2. Liquid Fuel – Kerosene oil, petrol, diesel, gasoline, alcohol etc. are the liquid fuels.
  3. Gaseous Fuel – Gobar gas, water gas (H2 + CO), coal gas. producer gas (N2 + CO), natural gas, liquid petroleum gas (LPG) etc. are the gaseous fuels.

Question 6.
Write about the following –

  1. First oil well of world
  2. First reservoir of oil in India
  3. Oil reserves of Rajasthan
  4. Other oil wells in India.

Answer:

  1. First oil well of world – World’s first well of oil was drilled in Pennsylvania (America) in 1859.
  2. First reservoir of oil in India – In 1867 the first reservoir of oil was find out at Mecum of Assam.
  3. Oil reservoirs of Rajasthan – In Rajasthan oil was discovered at Mangla, Bhagyam, Ashwarya, Guda, Rageshawari, Saraswati and Kamcshwari of Barmer.
  4. Other oil wells in India – Wells of oil are also found in areas of basin of rivers like Gujarat, Mumbai. Godavari, Krishna.

RBSE Solutions for Class 8 Science Chapter 18 Carbon and Fuel

Question 7.
Write the use of petroleum.
Answer:
Different forms of petroleum used continuously in Agriculture, industries, transport, telecom, houses and commercial work.

Question 8.
Write a short note on petroleum gas.
Answer:
Petroleum Gas – In fractional distillation, separation of petroleum gas takes place firstly at temperature 25°C to 30°C, it is mainly usable in vehicles and kitchens in the form of fuel. It has the mixture of ethane, propane, butane, iso-butane. This mixture can be liquefied easily at high pressure, which is called as liquefied petroleum gas (LPG). It is mostly used as fuel in houses. This gas gives up more heat in minimum time, This gas is smoke less, pollution less and lampblack less.

Question 9.
Give the information regarding compressed natural gas (CNG).
Answer:
CNG – During the time of mining of petroleum some gases are produced naturally called natural gas. It contain chiefly methane gas (CH4) It is used as a fuel in vehicles. It can he filled-up in cylinders in compressed form. So it is known as compressed natural gas.

Question 10.
What is combustion? Write the types of combustion with examples.
Answer:
Combustion – When any substance bums up in the presence of oxygen, this process is known as combustion. Types of Combustion – There are two types of combustion –

  1. Complete Combustion – When any substance gets proper quantity of oxygen, then it burns with blue flame, which is called as complete combustion. Example – Combustion of LPG.
  2. Incomplete Combustion – When any substance does not get proper amount of oxygen. Then it burns with yellow flame. It is called as incomplete combustion. Example – Combustion of wood.

Question 11.
Why the conservation of energy is essential?
Answer:
The store of energy are limited. So it is necessary that we should use the fuel in limitation and on necessity with proper way. By this energy will conserve and environment will also conserve, besides this the danger of global warming will decrease and facility of fuel will increase for long time.

RBSE Solutions for Class 8 Science Chapter 18 Carbon and Fuel

Question 12.
Being having the knowledge what will you suggest to the people for saving the fuel?
(OR)
Write the full name of P.C.R.A. Write the four ways suggested by them to save petrol – diesel.
(OR)
Write the given suggestions to save petrol – diesel by petroleum conservation research association.
Answer:
Full name of P.C.R.A. is the Petroleum Conservation Research Association. This association has given the following suggestions for saving the petrol-diesel –

  1. Drive your vehicle with constant and medium speed.
  2. Switch of the engine on red lights.
  3. Keep checking pressure of lyres.
  4. We should do regularly the maintenance of vehicle.

Question 13.
In your opinion what are the reasons to consider that LPG is a good fuel? Write any three.
Answer:
Due to following reasons LPG is a good fuel –

  1. LPG burn smokeless so there is no air pollution.
  2. LPG is having high ignition value, so it produce much heat.
  3. LPG completely hums and left no residue.
  4. LPG burns easily.
  5. On burning of LPG, no production of harmful gases.

Question 14.
Show by an activity that oxygen is necessary fur combustion.
Answer:
Activity – We will take a candle. Burn it with matchstick. Cover the burning candie with a glass or gas-jar. We will see that the candle extinguishes after some time. Result – The candle was burning as long as there was oxygen in the jar or glass. The candle was extinguished as the oxygen finished. It is that the presence of oxygen for combustion is necessary.

Long Answer Type Questions:

Question 1.
Describe in detail the different sources of fuel.
Answer:
Different Sources of Energy –

  1. Biomass – Those substances which are present in vegetables and animal’s body is called as biomass. Example – wood, dung, agriculture waste, etc.
  2. Wells of Crude Oil – Through the distillation process various petroleum substances are obtained as fuel.
  3. Coal Mines – From coal mines, obtained hard coal as fuel. Fuel can be obtained in three states –
    • Solid Fuel – Wooden coal, hard coal.
    • Liquid Fuel – Kerosene oil, diesel, petrol, gasoline, alcohol, etc. are liquid fuel.
    • Gaseous Fuel – Dung gas, water gas (H2 + CO), coal gas. producer gas (N2 + CO), natural gas, liquidified petroleum gas (LPG) etc. are gaseous fuel.

RBSE Solutions for Class 8 Science Chapter 18 Carbon and Fuel

Question 2.
How the coal is formed ¡n nature? Write about its types.
Answer:
Formation of Natural Coal –
Many years ago there were bushy forest in lower aquatic areas. Because of natural disaster like tlood, these forest collapsed under the land, due to congealation of soil on them those were destroyed. With the increment of depth, temperature increased. Because of high temperature and high pressure, plants which collapsed under the earth changed into coal.

In this way natural coal is formed. Slow process of coal alteration is called as carbonification or carbonization. Coal has mainly carbon. Because it is composed by vegetables residuals, thus it is a type of fossil fuels. Coal can be divided into four categories on the basis of the quantity of carbon –

  1. Peat – It consist approximate 60% carbon.
  2. Lignite – It consist approximate 67% carbon.
  3. Bitumen – It consist approximate 80% carbon.
  4. Anthracite – It consist approximate 90-98% carbon.

Question 3.
Explain the process of petroleum formation.
Answer:
Petroleum can be obtained through aquatic animals and plants. In oceans, dead animals and plants collapsed many years ago due to geological disruptions. Their bodies collapsed with sand and soil into the bottom of oceans. After many years. in the absence of air, high temperature and high pressure the dead animals and plants changed into petroleum and natural gas. Organism residue change into petroleum in the absence of oxygen (or air) and this process takes a long time of lakhs years.

Question 4.
Explain the process of refining of petroleum with diagram.
Answer:
Refining of Petroleum –
Refinement of petroleum is done by the fractional distillation process. Petroleum is a dark concentrated liquid of brown colour. It is a mixture of various hydrocarbons. Obtained crude oil by the mining cannot be use directly in the form of fuel. Different components of petroleum e.g. petroleum gas, neptha, diesel, kerosene, etc. have different boiling point.

After filling crude oil in the bottom of a vertical cylindrical container (fractionating column), boil it slowly. Then firstly petroleum gas. after that petrol, neptha, kerosene, diesel, etc. comes up due to evaporation, then all components are collects by the process of condensation. This process is called as fractional distillation.
In fractional distillation these products are formed –

  1. Petroleum gas
  2. Petrol
  3. Neptha
  4. Kerosene
  5. Diesel
  6. Lubricant oil
  7. Paraffin wax
  8. Petroleum charcoal, etc.

RBSE Solutions for Class 8 Science Chapter 18 Carbon and Fuel-8

Question 5.
Describe the obtained products by fractional distillation of petroleum.
Answer:
By fractional distillation the following petro products are obtained –

  1. Petroleum Gas – In fractional distillation, separation of petroleum gas takes place firstly at temperature 25°C to 30°C. It has mixture of ethane, propane, butane, iso-butane. This mixture can be liquidified easily at high pressure which is called as liquidified petroleum gas (LPG). It is used as fuel in kitchens.
  2. Petrol – Petrol separates out at 30°C to 120°C temperature. It is used in vehicle and also usable in drycleaning.
  3. Neptha – It separates out at temperature 120°C to 180°C. Neptha is used as fuel and in chemical reactions.
  4. Kerosene – It separates out at temperature 180°C to 260°C. It is used in kitchens (stove and lamp), in jet aeroplanes. in chimney, in lantern, etc.
  5. Diesel – It separates out at temperature 260°C to 340°C. It is used in heavy vehicles like truck, tractor and in electric generators.
  6. Lubricants – It separate outs at temperature 350°C.
  7. Paraffin Wax – This is also the product of petroleum, it is used in candle making, boot polish and paraffin papers.
  8. Petroleum Charcoal – It separate outs at temperature 600°C. It is a last residual of petrol’s fractional distillation. It is used in making roads.

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