Board | RBSE |
Class | Class 8 |
Subject | Science |
Chapter | Chapter 18 |
Chapter Name | Carbon and Fuel |
Number of Questions Solved | 39 |
Category | RBSE Solutions |
I. Multiple Choice Questions
Question 1.
Answers:
Question 2.
Fill in the blanks
Answers:
Question 3.
Put True (T) for correct and False (F) for incorrect for the following.
Answers:
Question 1.
Write the uses of petroleum gas.
Answer:
It is mainly useful as fuel in kitchen as cooking gas and automobiles.
Question 2.
We should sensibly use petrol and diesel like substances. Explain why?
Answer:
Question 3.
Write differences between diamond and graphite.
Answer:
S.No. | Properties | Graphite | Diamond |
(i) | Hard/Soft | It is a hazy/ opaque substance on touch. It is smooth and slippery. | Transparent, hard easily cracks. |
(ii) | Structure | In graphite carbon atom on same surface joins three carbon and form a hexagonal structure. Such surface are bonded with weak bonds hence they can slide on each other. So, they are soft. | In diamond it joins with other nearest four carbons and forms a hard three dimensional structure. |
(iii) | Electricity Conduction | It is good conductor of electricity. | It is bad conductor of electricity but good conductor of heat. |
(iv) | Use | It is used in electric arc and dry cells. | It is used in jewellery, cutting, grinding, hole passing etc. |
Question 4.
Compare L.P.G and Wood as Fuel.
Answer:
LPG | Wood | |
(i) | It gives more heat in less time. | (i) It gives less heat in more time. |
(ii) | It causes less air pollution. | (ii) It causes air pollution. |
(iii) | It bums completely. | (iii) It burns incompletely. |
(iv) | It doesn’t produces ash. | (iv) It produces ash. |
Question 5.
Name five compounds of carbon.
Answer:
Petrol, diesel, kerosene, wood and coal
Question 1.
Draw a well labelled diagram of diamond and graphite and explain their difference.
Answer:
S.No. | Properties | Graphite | Diamond |
(i) | Hard/Soft | It is a hazy/opaque substance on touch. It is smooth and slippery. | Transparent, hard easily cracks. |
(ii) | Structure | In graphite carbon atom on same surface joins three carbon and form a hexagonal structure. Such surface are bonded with weak bonds hence they can slide on each other. So, they are soft. | In diamond it joins with other nearest four carbons and forms a hard three dimensional structure. |
(iii) | Electricity Conduction | It is good conductor of electricity. | It is bad conductor of electricity but good conductor of heat. |
(iv) | Use | It is used in electric arc and dry cells. | It is used in jewellery, cutting, grinding, hole passing etc. |
Question 2.
Write your views in the following table and also discuss with other students.
Answer:
Advantages of uses of petroleum as fuel | Disadvantages of uses of petroleum as fuel |
Advantages of uses of petroleum as fuel | Disadvantages of uses of petroleum as fuel |
Petroleum is used as a fuel in vehicles and is used for dry washing/cleaning substance. | Petrol and diesel are the main causes of air pollution. |
These fuels are easily available. | Its reserves are on the verge of finishing. |
These fuels are convenient in their use. | Due to increase use of petroleum fuel, CO2 concentration is increasing hence global warming is increasing |
Question 3.
The use of petrol, diesel and kerosene is rising day by day. Their smoke is mixing with air and causing air polution. Write your suggestions and views for reducing air pollution.
Answer:
Suggestions to control pollution due to use of petroleum:
Question 4.
List the fuels used in daily life.
Answer:
Wood coal, Hard coal, Dung cakes, Agricultural wastes. Kerosene, diesel, petrol, gasoline, alcohol. Gobar gas, water gas (H2 + CO) Producer gas (N2 + CO), Natural gas, Liquefied petroleum gas (LPG) etc. are the fuel used in daily life.
Question 5.
Draw the diagram of extraction of petrol and label it.
Answer:
Question 6. .
Differentiate between complete and incomplete combustion. Explain with example.
Answer:
Complete combustion: When sufficient amount of oxygen is supplied to a burning substance, then it bums with blue flame, it is called complete combustion.
Example: combustion of LPG (liquefied Petroleum Gas).
Incomplete combustion: When any combustion substance do not get sufficient amount of oxygen supply, then it bums with yellow flame. It is called incomplete combustion.
Example: Burning of wood that causes air pollution.
I. Multiple Choice Questions
Question 1.
Which one of the following is petrochemical?
(a) Ammonia
(b) Coke
(c) Acetone
(d) Paraffin Wax
Question 2.
The fossil fuels are
(a) Inexhaustible
(b) Exhaustible
(c) Petroleum
(d) Laboratory made
Question 3.
Petroleum is found under the
(a) Sedimentary rocks
(b) Water
(c) Sand
(d) Coke
Question 4.
Main constituent of LPG is
(a) Methane
(b) Butane
(c) Ethane
(d) Propane
Question 5 .
The purest form of carbon is
(a) Coal gas
(b) Coal tar
(c) Coke
(d) Petroleum
Question 6.
The natural solid fuel is
(a) Coke
(b) Coal
(c) Coal tar
(d) Coal ga
Question 7.
The petroleum product which is used for road surfacing is
(a) Bitumen
(b) Coal gas
(c) Coke
(d) Coal
Question 8.
What is the leading source of energy used in the United States today?
(a) Coal
(b) Oil resources
(c) Natural gas
(d) Nuclear power
Question 9.
Dead organisms are transformed into petroleum and natural gas in
(a) Absence of air
(b) Presence of air
(c) Presence of sunlight
(d) None of these
Question 10.
Which of these is used as a solvent for dry cleaning
(a) Diesel
(b) Kerosene
(c) Petrol
(d) Paraffin wax
Answers:
1. (d)
2. (b)
3. (a)
4. (b)
5. (c)
6. (b)
7. (a)
8. (a)
9. (a)
10. (c)
Question 1.
Explain why fossil fuels are exhaustible natural resources?
Answer:
Fossil fuels are limited in nature, and are liable to be exhausted by different human activities. So they are called as exhaustible natural resources.
Question 2.
Define calorific value.
Answer:
The amount of heat given out by a unit mass of a fuel on complete combustion is called calorific value.
Question 3.
What is meant by carbonisation?
Answer:
The slow process of conversion of dead vegetation into coal is called as carbonisation.
Question 4.
Name the useful products obtained from coal.
Answer:
Coal can be subjected to destructive distillation to obtain useful products like coke, coal tar and coal gas.
Question 5.
Name the different places in India, where natural gas has been formed?
Answer:
In our country, natural gas has been formed in Tripura, Jaisalmer and in the offshore of Mumbai and in the Krishna-Godavari delta.
Question 1.
What is meant by inexhaustible and exhaustible natural resources?
Answer:
The inexhaustible natural resources are in unlimited quantity and are not likely to be exhausted by different human activities. For example, sunlight, air etc. The exhaustible natural resources are limited in nature and can be exhausted by the different human activities. For example; coal, petroleum and minerals etc.
Question 2.
What is destructive distillation?
Answer:
The process by which organic substances like wood, coal and oil are broken down by heat in the absence of air is known as destructive distillation.
Question 3.
What is coke? What are its uses?
Answer:
Coke is a tough, porous and black substance. It is almost pure form of carbon. Coke is used in the manufacture of steel and in the extraction of many metals.
Question 4.
Define combustion. List the substance undergoing complete and incomplete combustion.
Answer:
A chemical reaction that occurs when oxygen combines with other substances to produce heat and usually light is called combustion. For combustion of any substance the following three things are necessary:
Question 5.
Explain the allotropes of carbon.
Answer:
Carbon is found in different forms in nature which are divided into the following two parts:
Question 6.
How is coal formed?
Answer:
Coal is formed by the slow decomposition of forest woods that got buried under the earth’s crust due to natural calamities. Heat and pressure over millions of years changed these plants to coal.
Question 7.
What is natural gas? Write some of its uses?
Answer:
Natural gas is a fossil fuel. It is easy to transport. It is stored under high pressure as compressed natural gas (CNG). It is used in vehicles as fuel. It is compressed and fills in cylinders.
Question 1.
What are the different constituents of petroleum? What are the uses of petroleum products?
Answer:
The different constituents of petroleum are:
(a) LPG
(b) Petrol
(c) Kerosene
(d) Diesel
(e) Lubricating oil
(f) Paraffin wax
The different uses of petroleum products are:
(a) Petrol is used as motor fuel, aviation fuel and solvent for dry cleaning.
(b) Kerosene is used as fuel for stoves, lamp and jet aircrafts.
(c) Diesel is used as fuel for heavy motor vehicles, electric generators etc.
(d) Paraffin wax is used as ointment, candles and vaseline.
Question 2.
Define the constituents of crude oil.
Answer:
Crude oil consists of many useful fractions which can be obtained by subjecting it to the process of fractional distillation. These include petroleum gas, gasoline, kerosene, diesel, lubricating oils, paraffin wax and asphalt.
Question 3.
What is PCRA? What are its advices?
Answer:
Petroleum Conservation Research Association (PCRA) is an association involved in conservation of petroleum and the efficient utilization of fuel for both economical as well as environmental purposes.
The advices to save fuel by PCRA are:
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