Class 8 Chemistry - Coal And Petroleum

Coal can be drawn into wires.

If it is true then 1, false then 0.

Coal is neither malleable nor ductile.

It is brittle. It would crumble if you tried to draw it into a wire.

Hence, it is a false statement.

Why is charcoal considered to be a better fuel than wood?

Charcoal is considered to be a better fuel than wood because when the same amount of charcoal and wood is burnt, charcoal produces almost twice the heat produced by wood. Charcoal produces much less smoke than wood.

Which gas is obtained during the processing of coal?

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

_________ is the domestic fuel.

LPG (liquified petroleum gas) is used in homes for cooking and hence is known as domestic fuel. It is stored in cylinders.

Coal tar is a thick _______(black / yellow) liquid with pleasing smell.

Coal tar is the product of coal which is a thick black liquid having a pleasant smell. So the correct answer is black.

Imagine that all the exhaustible natural resources are exhausted by human activities. Then comment on the survival of living beings would be easily possible.

Exhaustible natural resources are known as non-renewable resources like coal,petroleum,natural gas etc. At the present rate of consumption these resources would soon deplete and our survival will be impossible as we shall go back to thousand years of stone age where means of transport were animal driven. All transports and industries providing basic needs are fuel dependent. So it will be difficult for human life to survive.

Coke floats on water due to the presence of air _____ in it.

Coke floats on water due to the presence of gaps, that are filled with air, between carbon atoms which makes it less dense than water. So, coke floats on water due to the presence of air gaps.

The full form of CNG is __________.

CNG is compressed natural gas, i.e. natural gas stored under high pressure. It is used as fuel in automobiles and for power generation. It is a clean fuel.

What is a natural gas?

Natural gas is a naturally occurring hydrocarbon gas mixture consisting primarily of methane, but commonly including varying amounts of other higher alkanes and a small percentage of $$CO_2$$. It mainly occurs deep under the earth's crust.

Natural gas is a very important fossil fuel because it is easy to transport through pipes. It is stored under high pressure as compressed natural gas (CNG).

Discuss the formation of coal in detail. What is this process called?

Coal was formed by the decomposition of large land plants and trees buried under the earth 300 million years ago. About 300 million years ago, the earth had dense forests in low-lying wetland areas. Due to natural processes like earthquakes, volcanoes and floods etc these forests were buried under the surface of the earth. As more soil was 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. The slow process by which the dead plants buried deep under the earth have become coal is called carbonisation. Since coal was formed from the remains of plants, therefore, coal is called a fossil fuel.

Name the petroleum product used for surfacing of roads.

Bitumen is the petroleum product used for surfacing of roads.

Explain why fossil fuels are exhaustible natural resources.

Exhaustible natural resources are those which have reserves of limited time span and will be finished in due course of time. These resources once depleted cannot be replenished back. It takes millions of years for the formation of fossil fuels. The rate at which we are using them is very fast compared to the rate of their formation. Due to this, fossil fuels are exhaustible in nature.

What are the advantages of using CNG and LPG as fuels?

The advantages of using compressed natural gas (CNG) and liquified petroleum gas (LPG) as fuels are:
1. They have low ignition temperatures.
2. They can be transported easily through pipelines.
3. They are clean fuels and do not give smoke when burnt.
4. They have high calorific value.

What precautions should be taken while using Liquified Petroleum Gas(LPG)?

We should take the following precautions while using LPG:
(i) If we feel a smell of gas, then the doors and windows should be opened at once to allow the gas to escape.
(ii) Do not turn on any electrical switches.
(iii) The rubber pipe connecting the gas cylinder to the gas stove should be checked from time to time for any wear and tear.

What are fossil fuels ? How were coal and petroleum formed ?

Fossil fuel:- A natural fuel such as coal or petroleum, formed from remains of living organisms buried inside the surface of the earth for millions and millions of years.

Coal and petroleum have been formed from remains of dead plants and animals which have been subjected to various biological and geological processes for many years. Coal is a natural resource that is obtained from the remains of trees and other plants that lived millions of years ago and petroleum is obtained from the remains of dead animals that too lived millions of years ago.

What is coal? Write its uses.

Coal is a naturally occurring black material that is a mixture of carbon and compounds of carbon-containing hydrogen, nitrogen, oxygen and sulphur. It is a major source of energy. It's a fossil fuel formed from the dead remains of plants buried deep inside the earth.

Uses of coal are as follows:

1) It is used as a fuel for heating purposes in homes and industries.

2) It is used as a fuel in thermal power plants for producing electricity.

3) It is used in the manufacture of coke, fuel gases like coal gas, synthetic petrol and synthetic natural gas.

As a good citizen, what steps will you take to conserve the energy sources?

As good citizens we will take the following steps to conserve the energy sources

1) Replace traditional incandescent light bulbs with halogen incandescent bulbs, compact fluorescent lights (CFLs), and light-emitting diode bulbs (LEDs).

2) Purchase energy-efficient appliances.

3) Sharing knowledge of energy conservation and its use to others.

Write down advantages and disadvantages of fossil fuel.

$$\text {Advantages of fossil fuels are} -$$

(i) Cheap and reliable

(ii) Safer over time

(iii) Contribute to overall welfare of the economy

(iv) High energy released through burning fossil fuel

$$\text {Disadvantages of fossil fuels are} -$$

(i) Finite resources

(ii) Combust to release harmful products in the environment.

(iii) Non-renewable

(iv) Pollution

How coal is formed?

Coal is formed in a step by step process:

1) Plants decay in the soil.

2) Peat is formed.

3) Peat changes to lignite [Soft brown coal form peat].

4) Bituminous coal is formed [Black & brittle, very polluting].

5) Anthracite coal is formed [highest amount of Carbon, clean burning].

Describe how coal is formed from dead vegetation. What is this process called?

Coal was formed by the decomposition of large land plants and trees buried under the Earth about 300 million years ago. About 300 million years ago, the Earth had dense forests in low-lying wet areas. Due to natural calamities like earthquakes, volcanoes, floods, etc. these forests got buried under the surface of the Earth. As more soil got deposited on them, they were compressed. As a result, the temperature also rose as they sank deeper and deeper. Due to high pressure and temperature and the absence of air, the wood of the buried forest plants and trees slowly got converted into coal.

The slow process by which the dead plants buried under the Earth have become coal is called $$\text{carbonization}$$. Since coal was formed from the remains of the plants, it is called a fossil fuel. Coal, which is mainly carbon, on heating produces mainly carbon dioxide gas and a lot of heat energy.

Give the full form of LPG and CNG.

LPG-Liquefied Petroleum Gas.

CNG-Compressed Natural Gas

Natural gas is very important fossil fuel. Support the statement with reason.

Natural gas is a very important first fuel because natural gas is another source of heat energy. It mainly consists of methane about $$97$$% and small quantities of ethane and propane.

(1) When natural gas in liquid form is subjected to high pressure we get compressed natural gas which is used as fuel in vehicles like cars, buses, and trucks. It is a good alternative to petrol and diesel because it does not cause any pollution.

(2) It reduces pollution and gives pure gas.

(3) It is used for cooking food, heating water manufacturing fertilizers, and producing electricity.

Fossil fuels are formed by the decomposition of biomass buried under the earth millions of years ago. Name any two fossil fuels.

The example of fossil fuels are as follow:

1) Coal

2) Petroleum

3) Natural gas

What are fossils?

A fossil is a trace of an animal or plant of a past geologic age that has been preserved in Earth's crust. Fossils can be broadly divided into body fossils and trace fossils.

Body fossil – The remains of the part (or all) of an actual organism. Example: Dinosaur bone.
Trace fossil – Trace fossils are traces or marks left behind by an organism. They show an organism was there, but are not the actual organism itself (which would be a body fossil). Dinosaur footprints and worm burrows are examples of trace fossils.

Fill in the blank in the following:

The gas supplied for cooking is _______.

The gas supplied for cooking is LPG (liquefied petroleum gas).

Write a short note on occurence of petroleum.

Petroleum is a liquid that occurs naturally between the rock under the earth. This consists of a mixture of different hydrocarbons and organic compounds. Some petroleum-produced chemical compounds are also obtained from other fossil fuels.

Petroleum is referred to as $$Black \ gold$$. This name itself is an indication of its importance to humans.

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.

What are fossil fuels ?

A natural fuel formed deep under the earth from the prehistoric remains of plants and animals is called fossil fuel.

How is coal formed? Explain.

Coal is formed when dead plant matter decays into peat and is converted into coal by the heat and pressure of deep burial over millions of years. Some iron and steel making and other industrial processes burn coal. The extraction and use of coal cause many premature deaths and many illnesses.

(a) What happens when carbon burns in air? Write the chemical equation of the reaction which takes place.
(b) Why are coal and petroleum called fossil fuels?
(c) Explain how coal was formed in the earth.
(d) Describe how petroleum was formed in the earth.
(e) Name a fossil fuel other than coal and petroleum.

(a) When carbon is burned in air, it forms carbon dioxide gas and releases a large amount of heat and some light:

$$C + O_{2} \rightarrow CO_{2} + Heat + Light$$

(b) Coal and petroleum are called fossil fuels because they were formed by the decomposition of the remains of the prehistoric plants and animals (fossils) buried under the earth long, long, ago.

(c) Coal was formed by the decomposition of large plants and trees buried under the earth millions of years ago. It is believed that millions of years ago, due to earthquakes and volcanoes, etc., the forests were buried under the surface of the earth and got covered with sand, clay, and water. Due to high temperature and high pressure inside the earth and in the absence of air, wood was converted into coal.

(d) Petroleum oil was formed by the decomposition of the remains of extremely small plants and animals buried under the sea millions of years ago. It is believed that millions of years ago, the microscopic plants and animals which lived in the sea have died. Their bodies sank to the bottom of the sea and were soon covered with mud and sand. The chemical effects of pressure, heat, and bacteria, converted the remains of microscopic plants and animals into petroleum oil and natural gas just as they converted forest trees into coal. This conversion took place in the absence of oxygen or air. The petroleum thus formed got trapped between two layers of impervious rocks (non-porous rock) forming an oil trap.

(e) Fossil fuel other than coal and petroleum is Natural gas.

A hard material $$X$$ which is mined from the earth is used as household fuel and also for the generation of electricity at thermal power stations. A soft material $$Y$$ is also used as a fuel in the form of candles. A gaseous material $$Z$$ which occurs along with petroleum is increasingly being used as a fuel in running vehicles in its compressed form.
(a) What are materials, $$X, Y$$ and $$Z$$?
(b) When materials $$X, Y$$ and $$Z$$ are burned separately:
(i) Which material burns by producing a yellow, luminous flame?
(ii) Which material ultimately burns without producing a flame?
(iii) Which material can burn in a gas stove by producing a blue flame?

(a). $$X$$ is coal, $$Y$$ is wax, and $$Z$$ is natural gas.

(b).

(i) $$Y$$ (wax) is the material that burns by producing a yellow, luminous flame.

(ii) $$X$$ (coal) is the material that ultimately burns without producing a flame.

(iii) $$Z$$ (natural gas) is the material that can burn in a gas stove by producing a blue flame.

Indicate the principle ingredients of the following:
Natural gas

Natural gas$$-CH_4, C_2H_6, C_3H_8$$

Natural gas is a naturally occurring hydrocarbon gas mixture consisting primarily of methane, but commonly including varying amounts of other higher alkanes,

Indicate the principle ingredients of the following:
Coal gas

The principle ingredients of the coal gas are $$H_2, CH_4, CO$$

Why is combustion of Liquefied Petroleum Gas $$(LPG)$$ a chemical change?

Combustion of Liquefied Petroleum Gas $$(LPG)$$ is a chemical change because, after its combustion, LPG's chemical composition changes and cannot be reversed using any physical method.

Write the full form of the following:
(a) LPG (b) CNG

(a) LPG – Liquefied Petroleum Gas.

(b) CNG – Compressed Natural Gas.

Name the petroleum product used as fuel for stoves, lamps and jet aircrafts.

Kerosene is a petroleum product. It is used as fuel for lamps, stoves, and Jet aircraft.

Fill in the blanks in the following sentence:
Petroleum, _ and ___ are fossil fuels.

Answer: coal, natural gas

Petroleum, coal and natural gas are fossil fuels. They are fuels that took hundreds of thousands of years to form from organic matter under high temperature and pressure conditions.

Fill in the blanks in the following sentences.
Coal is one of the ________ used to cook food.

Coal is one of the $$fuels$$ used to cook food.

Fill in the blanks in the following sentence.
Coal tar is a black, thick ____ with an _ smell.

Coal tar is a mixture of different carbon compounds. It is a thick, black liquid with an unpleasant smell.

Fill in the blank.

The slow process of conversion of dead vegetation into coal is called___________.

The slow process of conversion of dead vegetation into coal is called carbonization.

In the following sentence, find the jumbled word and write it in the correct form.
Rineryfe is a place where various fractions of petroleum are separated.

The jumbled word is Rineryfe and, the correct word is the refinery. $$Refinery$$ is a place where petroleum is separated into different fractions and purified.

The highlighted word in the following sentence has been jumbled up. Write it in their correct form.

$$Nutsgilh$$ is an example of inexhaustible natural resources.

$$Nutsgilh$$ is an example of inexhaustible natural resources.$$\Rightarrow \text{Sun-light}$$ is an example of inexhaustible natural resources.

Forests and coal are _________ natural resources.

Resources that get exhausted and are not available in nature in plenty are known as exhaustible natural resources. They take longer to get replenished.

Forests and coal are exhaustible natural resources.

Fill in the blank.
During the processing of coal to get a coke, coal tar and ________ are also obtained.

During the processing of coal to get a coke, coal tar and coal gas are also obtained. Coal gas is used as the fuel in many industries near coal processing plants.

Fill in the blanks.
The black thick liquid with ________ smell is known as coal tar.

The black thick liquid with $$\text{unpleasant}$$ smell is known as coal tar.

The underlined words in the following sentences have been jumbled up. Write them in their correct form.
Keenrose is a fuel used in jet aircrafts.

$$Keenrose$$ is a fuel used in jet aircrafts. $$\Rightarrow$$ $$\text{Kerosene}$$ is a fuel used in jet aircrafts.

Kerosene is a constituent of petroleum that is used widely in stoves, lamps and jet aircrafts.

The underlined words in the following sentences have been jumbled up. Write them in their correct form.
Umpetlore is a fossil fuel.

$$Umpetlore$$ is a fossil fuel. $$\Rightarrow$$ $$\text{petroleum }$$is a fossil fuel.

The underlined words in the following sentences have been jumbled up. Write them in their correct form.
(a) Loca is obtained from mines.

$$\text{ Coal}$$ is obtained from mines.

Fill in the blanks.
Coal and petroleum are formed from the dead remains of organisms and are known as _______.

Coal and petroleum are formed from the dead remains of organisms and are known as $$\text{fossil fuel.}$$

Write two important uses of coke.

Some important uses of coke are given below-

(i) Used in the extraction of metals.

Example- Zinc and Iron, etc.

(ii) It is used in steel manufacturing.

Look at the figure where petroleum and natural gas deposits are shown. Why do we find the oil layer above the water layer?

We find the oil layer above the water layer because oil is lightweight and thus floats over it. Also, the density of oil is less than water so it floats on the water surface.

Some natural resources are given in a box. Classify them into the exhaustible and inexhaustible natural resources. air, coal, natural gas, sunlight, petroleum, minerals, forests, oxygen.

$$Exhaustible Natural Resources$$- Natural gas, Coal, petroleum. Forests, Minerals

$$Inexhaustible Natural Resources$$ - Air, Oxygen, sunlight

Fill in the blanks.
The process of separating the various constituents of petroleum is known as__________.

The process of separating the various constituents of petroleum is known as $$\text{Petroleum Refining.}$$

Sunlight and air are inexhaustible natural resources. Comment.

Resources whose quantity doesn't depend on consumption or which don't fall to scarcity are known as inexhaustible natural resources. The quantity of sunlight and air doesn't depend on human consumption. That's why these are inexhaustible natural resources.

Write the characteristics and some important uses of coal.

Following are the important characteristics of coal-

It's a fossil fuel.
It's hard and combustible fuel.
It has carbon in prominent form.
It is a source of energy.

The important use of coal-

It is used to produce electricity and in homes used as fuel to cook.
It is used to make coke and coal gas.

We read in newspaper that burning of fuels is a major cause of global warming. Explain why.

Air pollution is the main issue caused by the use of fossil fuels in different areas. The burning of fossil fuels produces many dangerous gases such as Sulphur dioxide, Carbon Dioxide, etc. These gases are increasing the temperature of the earth by heating the atmosphere and air, The gases which vehicles, power plants, factories, houses, etc emit are helping to increase the temperature of the environment as well as the earth.

Imagine that all the exhaustible natural resources are exhausted by human activities. Do you think the survival of living beings would be possible? If yes, why? If not, why not?

No, The survival of human beings would be impossible if all the natural resources get exhausted. Fossil fuels are an essential part of human life. After oxygen and food, if something is very necessary for human life, it is a fossil fuel. Fossil fuels are helping to produce electricity which helps to run factories and where all the other essentials, a human might not survive for long. Apart from them, vehicles which humans use are run by using fossil fuels. Without fuel, human life will come to a stop.

Write some important uses of the various constituents of petroleum.

Below are the uses of important constituents of petroleum-

LPG gas is used in homes to cook food.
Petrol is used in automobiles.
Diesel is used in heavy vehicles.
Lubricating oils are used in vehicle' s engines.

Fill in the blanks and complete the story.

About 300 million years ago the earth had dense $$\text{forests}$$ in low lying wetland areas. Due to natural processes, like $$\text{floods}$$. these forests got buried under the $$\text{soil,}$$ As more $$\text{soil,}$$ deposited over them, they were compressed. The $$\text{temperature}$$ also rose as they sank deeper and deeper. Under high $$\text{pressure}$$ and high $$\text{temperature,}$$ dead plants got slowly converted into coal.

Match the items given in Column I with the items of Column II.

(A) Asphalt bitumen is a binding organic material made from the by-products of refined crude oil. It is used in road construction.

(B) CNG is compressed natural gas.

(C) Petroleum - Black gold is an informal term for oil or petroleum.

(D) Paraffin Wax - Paraffin wax used in candles, as a sealing agent and also used in vaseline.

Name the products obtained and their uses when coal is processed in industry.

The following products are obtained during coal processing:

Coal tar - Used for building roads, in the manufacture of synthetic drugs, explosives, perfumes, paints, plastics, etc.
Coke - Used to manufacture steel and in the extraction of metals.
Coal gas - Used as a fuel in industries.

Coal reserves are said to be enough to last for another hundred years. Do you think we need to worry in such case why or why not?

Coal reserves are very limited. A coal reserve lasts approximately 100 years only. By the speed humans are consuming coal, there's doubt if it lasts for 100 years now.

The field of coal consumption is increasing rapidly. From small houses to big factories and power suppliers are using coal prominently. This is resulting in the scarcity of coal. It takes millions of years to nature from this fossil fuel inside the earth. But the consumptions are too high that it would not last for long.

That is why we should use coal with care and responsibly. Apart from that, we should use other renewables forms of energy.

Why is it said that the fossil fuels will last only for a few hundred years?

Fossil fuels will last only for a few hundred years because they are exhaustible natural resources. It takes a very long time for the formation of fossil fuels. Their formation also requires very specific conditions. Therefore, their limited stock will last only for a few hundred years if consumed at a rate faster than the rate at which they are formed in nature.

What are the tips we must follow to save petrol/diesel/natural gas while driving?

We can follow the following tips to save petrol, diesel, and natural gas while driving:

We should drive our vehicles at a constant speed. Over speeding of vehicles wastes a lot of fuel.
On signals, we should switch off our vehicles. It helps to save a lot of fuel.

Why petrol is exhaustible natural resource, whereas sunlight is not Explain.

Petrol is a fossil fuel that is made by millions of years of decomposition of dead plants and animals inside the oceans. The places where it is found are very limited. Petrol is extracted from this fossil fuel. It's a very limited resource. The more limited it is, the more fiercely it's being used by humans. That's why petrol is an exhaustible resource. On the other hand, sunlight is a source of energy that is produced by the sun. In this process, a lot of energy is produced. And it's never going to end, at least until the people of earth are alive.

Complete the crossword with the help of the figure.
Across
Fuels obtained from dead remains of living organisms(1)
A process by which the various constituents of petroleum are separated. (2)
A porous black substance obtained from coal. (3)
Another name for motor fuel.(4)
Down
The substance is obtained by carbonization. (5)
Fuel for heavy motor vehicles. (6)
A petroleum product used for road surfacing. (7)
Dead remains of sea animals got converted into it. (8)

Across

Fuels obtained from dead remains of living organisms - Fossil fuels
A process by which the various constituents of petroleum are separated. Refining
A porous black substance obtained from coal. Coke
Another name for motor fuel. Petrol

Down

The substance is obtained by carbonization. Coal
Fuel for heavy motor vehicles. Diesel
A petroleum product used for road surfacing. Bitumen
Dead remains of sea animals got converted into it. Petroleum

1649772_1791799_ans_41df57cebdd640a3a56db1311354a5b5.png

Complete the crossword Fig 5.2 with the help of the
Across

A porous black substance obtained from coal. (4)

Coke

1649781_1791847_ans_796dd9bbcd2542e5b7fd8547fe069b88.png

Complete the crossword with the help of these hints:

$$Across$$
Fuels obtained from dead remains of living organisms.
A process by which the various constituents of petroleum are separated.
A porous black substance obtained from coal.
Another name for motor fuel.

$$Down$$
The substance obtained by carbonisation.
Fuel for heavy motor vehicles.
A petroleum product used for road surfacing.
Dead remains of sea animals got converted into it.

$$Across$$

1. Fuels obtained from dead remains of living organisms: FOSSIL FUELS

2. A process by which the various constituents of petroleum are separated: REFINING

3. A porous black substance obtained from coal: COKE

4. Another name for motor fuel: PETROL

$$Down$$

5. The substance obtained by carbonisation: COAL

6. Fuel for heavy motor vehicles: DIESEL

7. A petroleum product used for road surfacing: BITUMEN

8. Dead remains of sea animals got converted into it: PETROLEUM

1649769_1791793_ans_7da219944df344fa85a839c21f67c78a.png

Complete the crossword Fig. 5.2 with the help of the
Down
8.Dead remains of sea animals got converted into it.

Down-
8- Petroleum

1649800_1791893_ans_ab16972ed0724df5a77922187fb983b7.png

Complete the crossword with the help of the clues.

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 substance obtained from coal. (4)
4.Another name for motor fuel. (6)

Down
5.The substance obtained by carbonisation. (4)
6.Fuel for heavy motor vehicles.
7.A petroleum product used for road surfacing. (7)
8.Dead remains of sea animals got converted into it. (9)

Across:

1.FOSSIL FUELS

2.REFINING

3.COKE

4.PETROL

Down:

5.COAL

6.DIESEL

7.BITUMEN

8.PETROLEUM

1649796_1791879_ans_a2fb05575f6f4c1fb3d7719d27c44eb7.png

Complete the crossword Fig. 5.2 with the help of the
Down
A petroleum product used for road surfacing. (7)

Down-
7-Diesel

1649813_1791889_ans_15d0ce1de0364c62b838166d0d3d46fa.png

Complete the crossword Fig. 5.2 with the help of the
Another name for motor fuel.

Across-
4- $$Petrol$$

1649784_1791857_ans_0c249ec9ffaa4b3d837efc94af7d8a2b.png

Complete the crossword Fig. 5.2 with the help of the Down
The substance obtained by carbonisation. (4)

Down-
5- Coal

1649791_1791858_ans_5c6da1aa5f06495a91740f3f6402a9df.png

LPG is used for ________.

LPG (Liquid Petroleum Gas) is a flammable gas commonly used in residential heating, cooking, and as a fuel in cars, etc.

What steps would you suggest for the judicious use of fossil fuels?

Below are few points which are suggested for the judicious use of fossil fuels:

Use fossil fuels only when it is necessary to use and there are no other options.
Stop wastage of fuels, by switching off our vehicles at red lights.
Use renewable energy resources as they can be reproduced.

State full form of LPG and CNG. How are the two differ in their composition?

LPG ($$\text{Liquefied Petroleum Gas}$$): It is obtained from crude petroleum oil. It mainly contains gaseous compounds known as isobutane and butane. Popularly it is known as cooking gas. It is the best fuel for domestic purposes and in laboratories. It is available in cylinders. It is also supplied through pipes in big cities.

CNG ($$\text{Compressed Natural Gas}$$): It is produced along with crude oil. It mainly contains methane gas. It has become popular fuel for vehicles like three-wheeler scooters, cars, and buses. It is cheap fuel as well as pollution-free. It is used as a substitute for petrol.

The difference in composition:

LPG is obtained from crude petroleum oil. It mainly contains gaseous compounds known as isobutane and butane.

While CNG is produced along with crude oil. It mainly contains methane gas.

Natural gas is a _____ fuel?

Answer: fossil

Natural gas is a fossil fuel.

State uses of coal.

Uses of coal:

1. Coal is used as both domestic and industrial fuel.

2. It is used to prepare coke, coal gas, and coal tar.

3. In power generation coal is on the primary use worldwide.

Define carbonization.

The process of the slow conversion of vegetable matter into coal (carbon-rich substance) is called carbonization.

What are fuels? Give two examples of modern fuels.

$$Fuels$$: The substance which burns in air to produce a large amount of usable energy in the form of heat is called fuel.

Examples:

1. CNG (Compressed natural gas)

2. LPG (Liquefied natural gas)

Give two uses of coal.

Uses of coal:

It is used as both a domestic and industrial fuel.
It is used to produce electricity.

Describe the formation of coal.

The formation of coal took millions of years. Coal was formed by the bacterial decomposition of ancient vegetable matter hurried under successive layers of the earth.

Under the action of high temperature and pressure and in the absence of air, the decayed vegetable matter converted into coal.

Fill in the blanks:

Natural gas is an important __________.

Natural gas is an important fossil fuel.

We should sensibly use petrol and diesel like substances. Explain why?

1. A long process and time is needed to form oxide oil or natural fuels.

2. Their deposits are limited only for the next 100 years.

3. They cause air pollution.

4. They help in global warming.

Compare L.P.G and Wood as Fuel.

Sr.No.	LPG	Wood
(i)	It gives more heat in less time.	It gives less heat in more time.
(ii)	It causes less air pollution.	It causes air pollution.
(iii)	It burns completely.	It burns incompletely.
(iv)	It doesn't produce ash.	It produces ash.

What is water gas used for?

Uses of water gas:

It is used in industry to prepare a large number of organic compounds.
It is used as an industrial fuel.
It is used for the synthesis of ammonia.

What are the different types of coal? What are their uses?

The different types of coal are:

Peat: It is the first step of coal formation. It has high water content and less than $$60\%$$ carbon content.

Lignite: Lignite is a transformed form of peat and has around $$25-35\%$$ of carbon content. It is a lump of low-quality brown coal with a very little percentage of carbon in it. It is however used in the generation of electricity.

Bituminous: It is the most commonly found variety of coal in India is bituminous and has a carbon content of $$70-90\%$$. It is used for almost all daily requirements of coal.

Anthracite: It is the best-known variety of coal found in India. It has a carbon content of more than $$80\%$$ which makes it suitable for iron smelting.

State some uses of coke.

Uses of coke:

It was used for domestic heating in the past.
It is used for the extraction of metals.
It is used in the manufacture of steel.

Write the uses of petroleum gas.

It is mainly useful as fuel in kitchen as cooking gas and in automobiles.

Give two uses of coke.

Coke is used in the manufacture of steel
It is also used in the extraction of metals.

What are the different constituents of petroleum? What are the uses of petroleum products?

The different constituents of petroleum -LPG, Petrol, Kerosene, Diesel, Lubricating oil, Paraffin wax, Bitumen

The different uses of petroleum products are:

(a) LPG is used as a fuel for home and industry.

(b) Petrol is used as motor fuel, aviation fuel, and solvent for dry cleaning.

(d) Diesel is used as fuel for heavy motor vehicles, electric generators, etc.

(e) Lubricating oil is used in machines to lubricate the different parts.

(f) Paraffin wax is used as an ointment, candle, and vaseline.

(g)Bitumen is used in road surfacing and painting.

Name the different places in India, where natural gas has been formed?

In our country, natural gas has been formed in Tripura, Jaisalmer and in the offshore of Mumbai and in the Krishna-Godavari delta.

What is coke? What are its uses?

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.

Name the useful products obtained from coal.

Coal can be processed to obtain useful products like coke, coal tar and coal gas.

Define the constituents of crude oil.

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.

Explain why fossil fuels are exhaustible natural resources?

Fossil fuels are limited in nature, and are liable to be exhausted by different human activities. So they are called as exhaustible natural resources.

How is coal formed?

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.

What is meant by carbonisation?

The slow process of conversion of dead vegetation into coal is called as carbonisation.

What is natural gas? Write some of its uses?

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 used for the generation of electricity.

Why CNG is better than LPG as a fuel?

CNG is lighter than LPG. Hence, in case of leakage CNG goes up in the air while LPG spreads on the ground. Also, CNG has less amount of carbon thus, produce a negligible amount of carbon monoxide and carbon dioxide on combustion. Due to this CNG is much better than LPG.

Which type of coal is used in thermal power stations and railways?

Lignite is used in thermal power stations and railways since it is of lower grade and contains less percentage of carbon.

State the use of petroleum gas.

It is used in vehicles and as a fuel for cooking food .

How can we use the substance like petrol, diesel judiciously?

We can use petrol, diesel judiciously in the following ways:

i) Drive at constant and moderate speed as much as possible.

ii) Switch off the engine at traffic lights.

iii) Ensure correct tires pressure.

iv) Ensure regular maintenance of the vehicle.

What is PCRA? What are its advices?

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:

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

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

3. Ensure current tyre pressure.

4. Ensure regular maintenance of the vehicle.

What is petroleum refining?

Petroleum is a dark oily liquid. It is a mixture of various constituents such as petroleum gas, petrol, diesel, lubricating oil, paraffin, etc. The process of separating various constituents of petroleum is known as refining. It is carried out in a petroleum refinery.

We must use substances like petrol, diesel sparingly and very judiciously. Give reason.

If we overuse petrol, diesel there is a probability that they will be exhausted in the near future because their reserves are limited on earth and are non-renewable resources. Also, the burning of these fuels causes air pollution or produces gases (like carbon dioxide) which are responsible for global warming.

Due to these reasons, we must use substances like petrol, diesel sparingly and judiciously.

Write the uses of the substance given below:
(a) Petroleum

Petroleum is mostly used as a source of energy, being rich in combustible carbon in the production of electricity or running some sort of heat engine.

Raw petroleum (also known as crude oil) is used in three major ways: Transportation, electricity generation, and material production.

Which is the cooking gas that we get in cylinders for domestic use?

LPG (liquefied Petroleum Gas) is used as cooking gas for domestic use. LPG generally contains butane and propane gas which are liquefied under some pressure so that we can use it.

Why is ethyl mercaptan added to LPG?

The ethyl mercaptan is added to the LPG so that the leakage of the gas can be easily detected.

If a gas leak is suspected or if the fire spreads on a cylinder, what else could be done? Think it over.

If you are convinced that there is a gas leak, disconnect electricity from outside the home (switch off the main switches). Switch off the regulator and shift the cylinder to an empty space. Keep the windows and doors open. Request help from the Fire Force by calling the toll-free number 108.

Well trained rescue operators can put out the fire by covering the top end of the cylinder with wet sack to prevent the contact with oxygen. If the fire is in flat or the top story, then one should not try to escape using lifts. Only staircase should be used. Cover the nose and the mouth with soft cloth to avoid the intake of smoke or gases.

Some of you may be using LPG in your houses. What is the weight of the LPG filled in the cylinders supplied to your homes?

The weight of the LPG filled in the cylinders supplied to our homes is about $$14.2\ kg $$

If there is leakage of LPG it is mandatory to open the doors and windows. Why?

Immediately open all the doors and windows to your house so that the gas can escape. Never open electrical fans or even an exhaust fan. Let the gas escape naturally. Once you do that go outside the house and isolate the main electric supply. Be sure to evacuate yourself and others from the area.

Using this quantity of LPG for how many days can you cook?

This must be sufficient for a month.

If there is a leakage of LPG, does it rise up or come down in the atmosphere? Why?

LPG is heavier than air, so if it leaks, it will sink to the ground and accumulate in low lying areas.

Never switch on or off any electric switch when leakage of LPG is detected. Why?

It is usually advised not to switch on or off any of the electric switches if you detect a gas leakage. It is because the fumes of gas are highly flammable and even the smallest of sparks, due to switching of the electric switch, can ignite a huge fire.

How will you know if there is leakage in an LPG cylinder?

The telltale sign of an LPG cylinder leaking is the sulphurous odour of ethyl mercaptan. It is a smelly compound mixed with LPG as the gas in the cylinder are odourless.

Write the full form of LPG, what is its main constituent?

$$\textbf{Solution-}$$

$$\bullet$$ Full form of LPG is Liquefied Petroleum Gas

$$\bullet$$ Main constituents of LPG are Butane $$(C_4H_{10})$$ and Propane $$(C_3H_8)$$

$$\textbf{Additional Information-}$$

$$\bullet$$ LPG is a highly flammable in nature.
$$\bullet$$ Other hydrocarbons are also present in small quantity

What precautions are to be taken to avoid accidents due to LPG leakage? Discuss and record in the science diary.

• Examine the rubber tube at regular intervals and ensure that it does not have a leakage.
• Turn on the knob of the stove only after the regulator is turned on.
• Always buy LPG cylinders from authorized franchisees only
• Check that the cylinder has been delivered with the company seal and safety cap intact, do not accept the cylinder if the seal is broken.
• Please look for the due date of the test which is marked on the inner side of the cylinder stay plate and if this date is over, do not accept the cylinder
• Disconnect LPG regulator and affix safety cap on the cylinder when your gas stove is not in use for a prolonged period.
• Always store the LPG cylinder in an upright position and away from other combustible and flammable materials.
• Check for gas leaks regularly by applying soap solution on cylinder joints and Surakshapipes.

LNG and CNG are made from natural gases. What is the advantage of LNG over CNG?

LNG - liquefied natural gases can be conveniently transported by liquefaction. Can be changed into a gaseous state at the same temperature and can be distributed through pipes.

Coal is the most abundant fossil fuel on the earth. What are the substances obtained when coal is allowed to undergo distillation in the absence of air?

The substance formed when coal undergoes distillation in absence of air are ammonia, coal gas, coal-tar, coke, etc.

L.P.G is one of the common fuel for domestic use. Write full form of LPG.

The full form of LPG is Liquified Petroleum Gas. It is used as a domestic fuel.

Identify the relation and fill in the blanks
CNG: Fuel in Vehicles: LPG:_____

CNG is compressed natural gas which is used as a fuel in vehicles. LPG is a liquified petroleum gas and is used as a household fuel.

So the correct answer is

CNG: Fuel in vehicles: LPG:$$For\, domestic\, use$$

Using the relation from the first pair, complete the other.
LNG - Methane
LPG -

The main component of LNG is methane. Similarly the main component of LPG is butane.

LPG is one of the common fuels for domestic use. Which are the main constituent of LPG?

LPG is composed of hydrocarbons containing three or four carbon atoms. The main constituent of LPG are $$\text{Butane and propane} $$. Small concentration of other hydrocarbon may also be present.

A few news related to the energy crisis is given above. State two reasons for the energy crisis and write how we can overcome them.

The reasons for the energy crisis are:

Increase in population
Overexploitation of nonrenewable energy resources,
Industrialization
Urbanization.

The Remedial measures that can be taken to prevent it:

Population control
Use of renewable energy sources
Industrialization after finding required energy sources.

Identify the relation and fill in the blanks
LPG: Butane: LNG:______

$$Methane$$

LPG is composed of hydrocarbons containing three or four carbon atoms. The normal components of LPG thus, are propane $$(C_3H_8) $$ and butane $$(C_4H_{10}). $$

Liquefied natural gas, or LNG, is natural gas in its liquid form. LNG is neither corrosive nor toxic. Natural gas is primarily methane, with low concentrations of other hydrocarbons, water, carbon dioxide, nitrogen, oxygen, and some sulfur compounds.

What is the full form of LNG? List out its characteristics.

Liquefied Natural gas (LNG) is a natural gas that can be liquefied and transported to long distances conveniently. It can be again converted into a gaseous form at atmospheric temperature and distributed through pipelines.

Write the full expansion of LPG.

The full expansion of LPG is $$\text{liquefied Petroleum Gas}$$

What is the full form of LNG? List out its characteristics.

LNG full form is Liquefied Natural gas.

LNG is a natural gas that can be liquefied and transported to long distances conveniently. It can be again converted into a gaseous form at atmospheric temperature and distributed through pipelines.

What is solvent naphtha? What is its use?

During coal tar distillation, various fractions can be collected. The fraction distilling between $$413-433\ K$$ is called solvent naphtha.

Naphtha mainly contains xylenes and is used as a solvent for resins, rubbers, paints, etc.

Describe characteristics and uses of coke.

Characteristics of coke:
1. Tough
2. Porous

3. Black in colour

Uses of coke:
1. In manufacture of steel.
2. In the extraction of metals.

Fill in the blanks
The least polluting fuel for vehicles is?

Least polluting fuel for vehicles is compressed natural gas (CNG). CNG burns easily and give a lot of heat energy. It does not produce smoke and hence it is also a clean fuel.

What does $$LPG$$ stand for?

LPG stands for "Liquefied Petroleum Gas". It is a hydrocarbon gas that exists in a liquefied form. LPG is a colorless, low-carbon, and highly efficient fuel.

What type of hydrocarbons are present in high octane gasoline?

Branched chain aliphatic and/ or aromatic hydrocarbons are present in high octane gasoline.

What are petrochemicals? Write the names and uses of some of them.

$$\text{Petrochemicals}$$: All the synthetic fibers are prepared by a number of processes using raw materials or petroleum origin, called petrochemicals.

Or the useful substances obtained from petroleum and natural gas are termed petrochemicals.

Products made from petrochemicals include plastics, soaps, detergents, solvents, paints, drugs, fertilizer, pesticides, synthetic fibers and rubbers, and flooring and insulating materials. Petrochemicals are used to make such common products as aspirin, cars, clothing, electronic equipment, furniture, and much more.

Hydrogen gas obtained from natural gas is used in the production of urea (fertilizer).

What are petrochemicals. Discuss their utility.

Petrochemicals are chemicals that are derived from petroleum or natural gas. They are an essential part of the chemical industry as the demand for synthetic materials is growing continually and plays a major part in today's economy and society.

Petrochemicals are used to manufacture thousands of different products that we use daily such as plastics, medicines, cosmetics, furniture, appliances, electronics, solar power panels, and wind turbines, etc.

What do the abbreviations LPG and CNG stand for? Discuss their uses.

CNG stands for 'compressed natural gas', and LPG stands for 'liquefied petroleum gas'.

CNG is primarily used as a fuel in big vehicles like buses and trucks that return to base for refueling on a regular basis. CNG is also used as a fuel for cars.

LPG is a flammable gas commonly used in residential heating, cooking, and hot water systems. It is also used as a fuel in cars; and in industrial, agricultural, and manufacturing contexts.

Write the uses of the substance C.N.G.

Uses of CNG

1. It is used as a fuel in vehicles.

2. It is used for generation of electricity.

3. It is used to run electric heater used to heat homes in cold regions.

Coal and petroleum are called .... fuels.

Coal and petroleum are called $$\underline{fossil}$$ fuels. They are made of dead and decayed organisms buried deep under the earth for hundreds of thousands of years. Due to high temperature and pressure inside the earth, these organisms were converted into fossil fuels.

Coal And Petroleum - Class 8 Chemistry - Extra Questions

Coal can be drawn into wires.If it is true then 1, false then 0.