Class 8 Science Chapter 5

Coal and Petroleum (Detailed Explanation)

Introduction

Energy is one of the most important requirements for human life and development. Every activity we perform—such as cooking food, travelling, running industries, generating electricity, and operating machines—requires energy. Much of this energy comes from natural resources found in the Earth. Two very important natural energy resources are coal and petroleum.

Coal and petroleum are called fossil fuels because they were formed from the remains of plants and animals that lived millions of years ago. Over time, these remains were buried under layers of soil and rock. High temperature and pressure slowly transformed them into coal, petroleum, and natural gas.

These fuels are extremely valuable but limited in quantity. Therefore, it is important to understand how they are formed, how they are used, and why we must conserve them.

1. Fossil Fuels

Fossil fuels are fuels formed from the remains of ancient plants and animals buried deep inside the Earth for millions of years.

The main fossil fuels are:

Coal
Petroleum
Natural Gas

These fuels contain a large amount of stored energy. When they burn, they release heat energy that can be used for different purposes.

Characteristics of Fossil Fuels

They are formed over millions of years.
They are non-renewable resources.
They release energy when burned.
They are widely used for electricity, transport, and industries.

Because fossil fuels take millions of years to form, we cannot replace them quickly. This is why they must be used carefully.

2. Coal

Formation of Coal

Coal was formed about 300 million years ago from dense forests that existed in low-lying wet areas.

The process of coal formation occurred as follows:

Growth of plants
Dense forests existed in swampy areas.
Burial under soil
When plants died, they sank into the soil and were buried under layers of sediments.
High pressure and temperature
Over millions of years, heat and pressure increased due to layers of rocks.
Conversion into coal
The dead plants slowly converted into coal.

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

Carbonisation

Carbonisation is the process by which dead plant matter slowly changes into coal under high pressure and temperature in the absence of air.

3. Types of Coal

Coal exists in different forms depending on the amount of carbon present in it.

1. Peat

Lowest quality coal
Contains less carbon
Produces more smoke

2. Lignite

Brown coloured coal
Moderate carbon content
Used in power plants

3. Bituminous Coal

Most commonly used coal
Higher carbon content
Used in industries and electricity generation

4. Anthracite

Highest quality coal
Hard and shiny
Highest carbon content
Produces maximum heat

4. Products of Coal

Coal is not used only as fuel. When coal is processed in industries, it produces several useful products.

Destructive Distillation of Coal

When coal is heated in the absence of air, it breaks down into useful substances. This process is called destructive distillation.

The main products obtained are:

Coke
Coal Tar
Coal Gas

Coke

Coke is a tough, porous, black substance obtained from coal.

Properties

Almost pure carbon
Hard and porous
Burns with very little smoke

Uses

Used in the manufacture of steel
Used as a fuel in blast furnaces
Used in the extraction of metals from ores

Coal Tar

Coal tar is a thick, black liquid with a strong smell.

It contains many useful chemicals.

Products made from Coal Tar

Dyes
Drugs
Naphthalene balls
Perfumes
Plastics
Pesticides
Paints
Synthetic fibres
Roads (tar for road construction)

Earlier, coal tar was the main source of chemicals. Today, most chemicals are produced from petroleum products.

Coal Gas

Coal gas is obtained during the processing of coal to make coke.

Uses

Used as fuel in industries
Earlier used for street lighting

5. Petroleum

Petroleum is another important fossil fuel. It is a dark, oily liquid found deep under the Earth between layers of rocks.

Petroleum is also called crude oil.

Formation of Petroleum

Petroleum was formed from the remains of tiny marine organisms that lived in seas and oceans millions of years ago.

The process happened as follows:

Marine organisms died and sank to the sea floor.
Their remains were buried under layers of sand and clay.
High pressure and temperature transformed them into petroleum and natural gas.
Oil accumulated in porous rocks deep underground.

6. Petroleum Refining

Crude petroleum cannot be used directly. It must first be separated into useful components.

This process is called petroleum refining.

Petroleum is separated by a process known as fractional distillation in oil refineries.

Major Petroleum Refineries in India

Some important refineries are located at:

Digboi (Assam)
Mathura
Panipat
Mumbai
Chennai
Jamnagar

7. Products of Petroleum

Petroleum is separated into several useful products.

1. Petroleum Gas (LPG)

Used as cooking gas in homes
Used as fuel in industries

2. Petrol

Used in cars, motorcycles, and scooters
Highly volatile fuel

3. Kerosene

Used as fuel in stoves and lamps
Used as aviation turbine fuel

4. Diesel

Used in buses, trucks, tractors
Used in generators

5. Lubricating Oil

Used in machines to reduce friction

6. Paraffin Wax

Used to make candles, ointments, wax paper, cosmetics

7. Bitumen

Used for road construction

8. Natural Gas

Natural gas is another fossil fuel found with petroleum deposits.

It is mainly composed of methane gas.

Properties

Colourless
Odourless
Highly flammable
Clean fuel

Uses

Used in power plants
Used as fuel in industries
Used as CNG (Compressed Natural Gas) in vehicles
Used in households as PNG (Piped Natural Gas)

Advantages of Natural Gas

Produces less pollution
Easy to transport through pipelines
High calorific value

9. Petrochemicals

Petroleum products are used to manufacture many chemicals called petrochemicals.

Products made from Petrochemicals

Plastics
Synthetic fibres (nylon, polyester)
Detergents
Synthetic rubber
Fertilisers
Explosives

Petrochemicals play an important role in modern industries.

10. Non-Renewable Natural Resources

Coal, petroleum, and natural gas are called non-renewable resources because they take millions of years to form.

Once these fuels are used up, they cannot be replaced quickly.

If we continue using them rapidly, they may get exhausted in the future.

11. Problems Caused by Fossil Fuels

1. Air Pollution

Burning coal and petroleum releases harmful gases such as:

Carbon dioxide
Sulphur dioxide
Nitrogen oxides

These gases cause pollution and breathing problems.

2. Global Warming

Carbon dioxide increases the greenhouse effect and causes global warming.

3. Acid Rain

Sulphur dioxide and nitrogen oxides combine with rainwater to produce acid rain, which damages crops, buildings, and forests.

4. Environmental Damage

Oil spills and coal mining can damage ecosystems.

12. Conservation of Fossil Fuels

Since fossil fuels are limited, we must conserve them.

Ways to Conserve Fossil Fuels

Use public transport.
Switch off vehicles at traffic lights.
Use energy-efficient appliances.
Promote renewable energy such as solar and wind.
Reduce unnecessary electricity use.
Encourage carpooling.
Develop alternative fuels like biofuel.

13. Alternative Sources of Energy

To reduce dependence on fossil fuels, scientists are developing alternative energy sources such as:

Solar Energy
Wind Energy
Hydroelectric Energy
Biogas
Geothermal Energy

These are renewable and environmentally friendly.

Conclusion

Coal and petroleum are among the most important natural resources that support modern civilization. They provide energy for industries, transport, electricity generation, and daily household activities. These fuels were formed millions of years ago from the remains of plants and animals through natural processes involving heat and pressure.

Coal produces useful substances such as coke, coal tar, and coal gas, while petroleum is refined to obtain petrol, diesel, kerosene, LPG, lubricating oil, paraffin wax, and bitumen. Natural gas is another valuable fossil fuel that burns cleanly and is widely used in homes and industries.

However, fossil fuels are non-renewable and their excessive use leads to environmental problems such as pollution, global warming, and acid rain. Therefore, it is extremely important to use these resources wisely and conserve them for future generations.

Adopting renewable energy sources and reducing unnecessary consumption can help protect our environment and ensure sustainable development.

Renewable Energy Sources (Detailed Explanation)

Introduction

Energy is essential for human life and development. It is required for cooking food, running machines, generating electricity, transportation, lighting homes, and operating industries. Traditionally, most of the energy used in the world comes from fossil fuels such as coal, petroleum, and natural gas. However, these resources are limited and take millions of years to form. Their excessive use also causes environmental problems such as air pollution, global warming, and climate change.

Because of these issues, scientists and governments around the world are focusing on renewable energy sources. Renewable energy sources are natural sources of energy that are continuously replenished by nature and do not get exhausted easily. They are environmentally friendly and sustainable for long-term use.

Renewable energy plays an important role in reducing pollution and ensuring a clean and healthy environment for future generations. Common examples of renewable energy sources include solar energy, wind energy, hydro energy, geothermal energy, biomass energy, and tidal energy.

What is Renewable Energy?

Renewable energy is energy obtained from natural sources that are constantly replenished. These sources are available in unlimited quantities and can be used repeatedly without being depleted.

Characteristics of Renewable Energy

They are naturally replenished.
They do not get exhausted easily.
They produce little or no pollution.
They are environmentally friendly.
They help reduce dependence on fossil fuels.

Renewable energy sources are also called non-conventional energy sources because they are alternatives to traditional fossil fuels.

1. Solar Energy

Solar energy is the energy obtained from the Sun. The Sun is the ultimate source of energy for almost all life on Earth. It produces enormous amounts of heat and light energy every day.

Solar energy can be captured using solar panels or solar collectors and converted into electricity or heat.

How Solar Energy Works

Solar panels contain special materials called photovoltaic cells. These cells absorb sunlight and convert it directly into electricity. This process is known as the photovoltaic effect.

Uses of Solar Energy

Solar panels generate electricity for homes and industries.
Solar cookers are used to cook food using sunlight.
Solar water heaters heat water for domestic use.
Solar street lights illuminate roads and parks.
Solar calculators and small devices operate using solar cells.

Advantages of Solar Energy

Unlimited source of energy.
Environmentally friendly.
Reduces electricity bills.
Low maintenance cost.

Disadvantages

Depends on sunlight.
Not available during night or cloudy weather.
Installation cost can be high.

2. Wind Energy

Wind energy is the energy obtained from moving air. Wind is produced due to uneven heating of the Earth’s surface by the Sun.

Wind energy is captured using large machines called wind turbines.

How Wind Energy Works

Wind turns the blades of a wind turbine. These rotating blades spin a generator inside the turbine, producing electricity.

Large groups of wind turbines form wind farms that generate electricity for cities and industries.

Uses of Wind Energy

Generating electricity in wind farms.
Pumping water in rural areas.
Grinding grains using traditional windmills.

Advantages of Wind Energy

Renewable and unlimited.
No air pollution.
Low operating cost.

Disadvantages

Wind is not always constant.
Requires large open areas.
Turbines may produce noise.

3. Hydroelectric Energy (Water Energy)

Hydroelectric energy is energy obtained from flowing water. Water stored in dams contains potential energy. When water flows down from a height, it spins turbines that generate electricity.

This process is used in hydroelectric power plants.

How Hydroelectric Power Works

Water is stored in a large reservoir behind a dam.
When water is released, it flows through pipes.
The flowing water spins turbines.
The turbines drive generators that produce electricity.

Uses of Hydroelectric Energy

Electricity generation
Irrigation systems
Flood control
Water supply

Advantages

Renewable energy source
No air pollution
Reliable electricity production

Disadvantages

Construction of dams is expensive
Large areas of land may be submerged
Can affect local ecosystems

4. Geothermal Energy

Geothermal energy is the heat energy obtained from deep inside the Earth. The interior of the Earth is extremely hot due to molten rocks called magma.

In certain regions, underground water becomes heated by hot rocks and turns into steam. This steam can be used to generate electricity.

How Geothermal Energy Works

Wells are drilled deep into the Earth.
Hot water or steam rises to the surface.
The steam turns turbines connected to generators.
Electricity is produced.

Uses of Geothermal Energy

Electricity generation
Heating homes and buildings
Heating greenhouses
Industrial processes

Advantages

Continuous energy supply
Low pollution
Reliable power generation

Disadvantages

Available only in certain locations
High initial cost
Risk of releasing underground gases

5. Biomass Energy

Biomass energy is energy obtained from organic materials such as plants, agricultural waste, animal dung, and wood.

These materials contain stored solar energy that can be released when they are burned or converted into biofuels.

Types of Biomass Energy

Biogas
Biofuels
Wood energy

Biogas

Biogas is produced by the decomposition of animal dung and organic waste in the absence of oxygen.

Biogas plants are commonly used in rural areas.

Uses of Biomass Energy

Cooking fuel
Electricity generation
Heating buildings
Producing biofuels such as ethanol and biodiesel

Advantages

Uses waste materials
Reduces environmental pollution
Renewable energy source

Disadvantages

Produces smoke when burned
Requires proper waste management
Lower energy efficiency compared to fossil fuels

6. Tidal Energy

Tidal energy is produced from the movement of ocean tides. Tides occur due to the gravitational pull of the Moon and the Sun on the Earth’s oceans.

The rising and falling of water can be used to generate electricity.

How Tidal Energy Works

A dam called a tidal barrage is built across a sea inlet.
As tides rise and fall, water flows through turbines.
The turbines rotate generators to produce electricity.

Advantages

Predictable and reliable
Renewable energy source
No air pollution

Disadvantages

Very expensive to build
Limited suitable locations
Can affect marine ecosystems

Importance of Renewable Energy

Renewable energy is becoming increasingly important for the future of the planet.

Major Benefits

Reduces dependence on fossil fuels
Decreases environmental pollution
Helps fight climate change
Provides sustainable energy supply
Creates new employment opportunities

Many countries are investing heavily in renewable energy technologies to create a cleaner and more sustainable energy system.

Renewable Energy in India

India is one of the leading countries in developing renewable energy.

Important initiatives include:

Large solar parks
Wind energy farms
Hydroelectric projects
Promotion of biogas plants
Rooftop solar panel installations

India aims to increase the share of renewable energy in electricity production to reduce pollution and ensure energy security.

Challenges of Renewable Energy

Although renewable energy has many advantages, it also faces some challenges:

High installation cost
Dependence on natural conditions
Energy storage problems
Need for advanced technology
Land requirement for large projects

Scientists are continuously working to improve renewable energy technologies and overcome these challenges.

Future of Renewable Energy

The future of energy lies in renewable sources. As fossil fuels become scarce and environmental concerns grow, renewable energy will become more important.

Technological advancements are making renewable energy more efficient and affordable. Solar panels are becoming cheaper, wind turbines are becoming more powerful, and energy storage technologies such as batteries are improving.

In the future, most of the world’s energy may come from renewable sources.

Conclusion

Renewable energy sources are essential for sustainable development and environmental protection. Unlike fossil fuels, renewable energy sources such as solar, wind, hydroelectric, geothermal, biomass, and tidal energy are naturally replenished and do not get exhausted easily.

These energy sources produce less pollution and help reduce the harmful effects of climate change. Although renewable energy technologies require investment and development, they offer long-term benefits for society and the environment.

By promoting renewable energy and using energy wisely, we can ensure a clean, safe, and sustainable future for generations to come. Governments, industries, and individuals must work together to increase the use of renewable energy and reduce dependence on fossil fuels.

80 MCQs

1–20 Basic MCQs

Coal is a type of
A. Renewable resource
B. Non-renewable resource
C. Man-made resource
D. Unlimited resource
Ans: B
Coal is mainly composed of
A. Nitrogen
B. Carbon
C. Hydrogen
D. Oxygen
Ans: B
The process of converting dead vegetation into coal is called
A. Carbonisation
B. Fossilisation
C. Sedimentation
D. Combustion
Ans: A
Petroleum is also known as
A. Black gold
B. White gold
C. Green gold
D. Blue gold
Ans: A
Petroleum is found
A. On mountains
B. Under oceans and land
C. In deserts only
D. In rivers
Ans: B
The process of separating petroleum into different parts is called
A. Filtration
B. Distillation
C. Fractional distillation
D. Evaporation
Ans: C
The first oil well in India was drilled in
A. Digboi
B. Mumbai
C. Delhi
D. Assam city
Ans: A
CNG stands for
A. Compressed Natural Gas
B. Common Natural Gas
C. Carbon Natural Gas
D. Chemical Natural Gas
Ans: A
Natural gas is mainly composed of
A. Methane
B. Oxygen
C. Nitrogen
D. Carbon dioxide
Ans: A
Coke is obtained from
A. Petroleum
B. Coal
C. Natural gas
D. Wood
Ans: B
Coal tar is used for making
A. Roads
B. Perfumes
C. Medicines
D. All of these
Ans: D
The hardest form of coal is
A. Peat
B. Lignite
C. Anthracite
D. Bituminous
Ans: C
Petroleum products include
A. Petrol
B. Diesel
C. Kerosene
D. All of these
Ans: D
The gas obtained from petroleum refining is
A. LPG
B. Hydrogen
C. Oxygen
D. Nitrogen
Ans: A
LPG stands for
A. Liquid Petroleum Gas
B. Liquefied Petroleum Gas
C. Limited Petroleum Gas
D. Low Petroleum Gas
Ans: B
Fossil fuels include
A. Coal
B. Petroleum
C. Natural gas
D. All of these
Ans: D
Coal tar has about
A. 100 substances
B. 200 substances
C. 300 substances
D. 400 substances
Ans: B
Bitumen is used for
A. Cooking
B. Road surfacing
C. Lighting
D. Fertilizers
Ans: B
The main component of natural gas is
A. Methane
B. Ethane
C. Propane
D. Butane
Ans: A
Fossil fuels were formed millions of years ago from
A. Plants and animals
B. Rocks
C. Soil
D. Metals
Ans: A

21–40 Intermediate MCQs

Coal gas is obtained during the production of
A. Coke
B. Coal tar
C. Petroleum
D. Natural gas
Ans: A
The cleanest fossil fuel is
A. Coal
B. Petrol
C. Natural gas
D. Diesel
Ans: C
Petrochemicals are used to make
A. Plastic
B. Synthetic fibres
C. Detergents
D. All of these
Ans: D
The thick black liquid obtained from coal is
A. Coke
B. Coal tar
C. Coal gas
D. Bitumen
Ans: B
The first refinery in India was set up at
A. Digboi
B. Mumbai
C. Delhi
D. Chennai
Ans: A
Petroleum is found trapped between
A. Layers of rock
B. Soil layers
C. Water layers
D. Air layers
Ans: A
Diesel is mainly used in
A. Cars
B. Trucks and buses
C. Aircraft
D. Cycles
Ans: B
Kerosene is mainly used for
A. Cooking and lighting
B. Road making
C. Fertilizers
D. Plastics
Ans: A
The process of coal formation takes
A. 10 years
B. 100 years
C. Millions of years
D. 1 year
Ans: C
Coal is formed from
A. Animals
B. Plants
C. Rocks
D. Minerals
Ans: B
Petrol is mainly used as
A. Fuel for vehicles
B. Fertilizer
C. Road making
D. Plastic
Ans: A
The gas used in kitchens is
A. LPG
B. Oxygen
C. Nitrogen
D. Hydrogen
Ans: A
The refining of petroleum is done in
A. Mines
B. Refineries
C. Laboratories
D. Fields
Ans: B
Petrochemicals are made from
A. Petroleum
B. Coal
C. Water
D. Oxygen
Ans: A
Bitumen is obtained from
A. Petroleum
B. Coal
C. Natural gas
D. Wood
Ans: A
The process of extracting minerals from the earth is
A. Mining
B. Farming
C. Digging
D. Drilling
Ans: A
Petroleum deposits are usually found
A. Deep underground
B. On the surface
C. In rivers
D. In forests
Ans: A
The liquid fuel used in airplanes is
A. Petrol
B. Diesel
C. Kerosene
D. LPG
Ans: C
Natural gas is stored in
A. Cylinders
B. Pipelines
C. Tanks
D. All of these
Ans: D
Fossil fuels are limited because they are
A. Renewable
B. Non-renewable
C. Recyclable
D. Unlimited
Ans: B

41–60 Advanced MCQs

The residue left after petroleum refining is
A. Bitumen
B. Coke
C. Coal gas
D. LPG
Ans: A
Which fuel causes least pollution?
A. Coal
B. Petrol
C. Natural gas
D. Diesel
Ans: C
The use of fossil fuels increases
A. Oxygen
B. Carbon dioxide
C. Nitrogen
D. Hydrogen
Ans: B
Coal is mainly used in
A. Thermal power plants
B. Vehicles
C. Aircraft
D. Ships
Ans: A
Petrochemicals help make
A. Nylon
B. Polyester
C. Plastic
D. All of these
Ans: D
The black sticky substance used for roads is
A. Coal tar
B. Bitumen
C. Coke
D. LPG
Ans: B
Petroleum products are obtained by
A. Fractional distillation
B. Filtration
C. Evaporation
D. Sedimentation
Ans: A
Natural gas pipelines connect
A. Cities
B. Villages
C. Industries
D. All of these
Ans: D
Which fuel is used in gas stoves?
A. LPG
B. Coal
C. Diesel
D. Petrol
Ans: A
Which fossil fuel is used to produce coke?
A. Coal
B. Petroleum
C. Gas
D. Wood
Ans: A
The formation of petroleum occurred
A. Millions of years ago
B. Hundreds of years ago
C. Thousands of years ago
D. Recently
Ans: A
Petroleum refining produces
A. Petrol
B. Diesel
C. Lubricating oil
D. All of these
Ans: D
The main fuel used in automobiles is
A. Petrol
B. Diesel
C. Both A and B
D. Coal
Ans: C
Which is not a fossil fuel?
A. Coal
B. Petroleum
C. Natural gas
D. Solar energy
Ans: D
Coke is used in
A. Steel manufacturing
B. Cooking
C. Lighting
D. Farming
Ans: A
Petrochemicals are useful for
A. Fertilizers
B. Plastics
C. Synthetic rubber
D. All of these
Ans: D
LPG is stored in
A. Liquid form
B. Solid form
C. Gas form
D. Powder form
Ans: A
Which product is used for lubricating machines?
A. Lubricating oil
B. Petrol
C. Coal
D. Coke
Ans: A
Natural gas can be transported by
A. Pipelines
B. Cylinders
C. Tankers
D. All of these
Ans: D
The use of fossil fuels leads to
A. Air pollution
B. Water purification
C. Oxygen increase
D. Soil fertility
Ans: A

61–80 Higher Level MCQs

Coal mines are mostly found in
A. Jharkhand
B. Odisha
C. Chhattisgarh
D. All of these
Ans: D
Natural gas used in vehicles is called
A. LPG
B. CNG
C. PNG
D. LNG
Ans: B
PNG stands for
A. Piped Natural Gas
B. Pure Natural Gas
C. Petroleum Natural Gas
D. Public Natural Gas
Ans: A
Which petroleum product is used in jet engines?
A. Petrol
B. Diesel
C. Kerosene
D. LPG
Ans: C
Fossil fuels are also called
A. Renewable fuels
B. Conventional fuels
C. Non-renewable fuels
D. Modern fuels
Ans: C
Bitumen replaced
A. Coal tar
B. Petrol
C. Diesel
D. Coke
Ans: A
The largest use of coal is for
A. Electricity generation
B. Cooking
C. Lighting
D. Plastic
Ans: A
Which is the cleanest domestic fuel?
A. Coal
B. Wood
C. LPG
D. Petrol
Ans: C
Petroleum resources should be
A. Wasted
B. Conserved
C. Burned more
D. Ignored
Ans: B
Conservation of fossil fuels helps in
A. Saving resources
B. Reducing pollution
C. Protecting environment
D. All of these
Ans: D
The main fuel in thermal power plants is
A. Coal
B. Petrol
C. Diesel
D. LPG
Ans: A
Petrochemicals are used to produce
A. Polythene
B. PVC
C. Synthetic rubber
D. All of these
Ans: D
Coal, petroleum and natural gas are called
A. Fossil fuels
B. Minerals
C. Metals
D. Ores
Ans: A
Which gas is mainly responsible for global warming?
A. Oxygen
B. Carbon dioxide
C. Nitrogen
D. Hydrogen
Ans: B
Natural gas is considered an eco-friendly fuel because
A. It burns completely
B. It produces less pollution
C. It is efficient
D. All of these
Ans: D
Coke is almost pure
A. Carbon
B. Oxygen
C. Hydrogen
D. Nitrogen
Ans: A
The formation of fossil fuels requires
A. High temperature and pressure
B. Low temperature
C. Water only
D. Air only
Ans: A
Petroleum is a
A. Fossil fuel
B. Mineral oil
C. Natural resource
D. All of these
Ans: D
Which is not obtained from petroleum?
A. Petrol
B. Diesel
C. Coal
D. Kerosene
Ans: C
The best way to save fossil fuels is
A. Using public transport
B. Saving electricity
C. Using renewable energy
D. All of these
Ans: D

Here are 10 Case Study–Based Questions from Class 8 Science – Chapter: Coal and Petroleum (Minerals and Petroleum) according to CBSE pattern.

Case Study Based Questions

Case Study 1: Formation of Coal

Millions of years ago, dense forests covered the Earth. Due to natural processes such as floods and earthquakes, many plants got buried under soil. Over time, high pressure and temperature converted these dead plants into coal.

Questions

The process of converting dead vegetation into coal is called:
a) Combustion
b) Carbonisation
c) Distillation
d) Filtration
Coal mainly contains:
a) Hydrogen
b) Carbon
c) Oxygen
d) Nitrogen
Coal formation takes:
a) A few years
b) Hundreds of years
c) Millions of years
d) One year
Coal is a:
a) Renewable resource
b) Non-renewable resource
c) Unlimited resource
d) Artificial resource

Case Study 2: Petroleum Extraction

Petroleum is found deep under the earth between layers of rock. Oil wells are drilled to bring petroleum to the surface. Crude petroleum is then transported to refineries where it is separated into different useful products.

Questions

Petroleum is also called:
a) Black gold
b) White gold
c) Yellow gold
d) Green gold
The process of separating petroleum into useful components is:
a) Filtration
b) Fractional distillation
c) Evaporation
d) Sedimentation
Petroleum is found:
a) On the surface
b) Between rock layers
c) In rivers
d) In forests
The places where petroleum is processed are called:
a) Mines
b) Refineries
c) Farms
d) Factories

Case Study 3: Petroleum Products

Crude petroleum is refined to obtain many useful products such as petrol, diesel, kerosene, lubricating oil and bitumen. These products are used for transportation, cooking, electricity generation and road construction.

Questions

Which petroleum product is used in vehicles?
a) Petrol
b) Diesel
c) Both a and b
d) Coal
Bitumen is mainly used for:
a) Cooking
b) Road construction
c) Fertilizers
d) Medicines
Kerosene is used for:
a) Lighting and cooking
b) Making plastic
c) Making steel
d) Farming
Lubricating oil is used for:
a) Cooking
b) Running machines smoothly
c) Cleaning water
d) Lighting lamps

Case Study 4: Natural Gas

Natural gas is a fossil fuel found with petroleum deposits. It is mainly composed of methane. Natural gas is transported through pipelines and used as a clean fuel for vehicles and cooking.

Questions

The main component of natural gas is:
a) Methane
b) Nitrogen
c) Oxygen
d) Hydrogen
CNG stands for:
a) Compressed Natural Gas
b) Common Natural Gas
c) Carbon Natural Gas
d) Clean Natural Gas
Natural gas is considered:
a) Polluting fuel
b) Clean fuel
c) Solid fuel
d) Artificial fuel
Natural gas is transported mainly through:
a) Trucks
b) Pipelines
c) Ships
d) Air

Case Study 5: Coal Products

Coal is processed to obtain useful products like coke, coal tar and coal gas. Coke is used in the manufacture of steel. Coal tar is used for making chemicals, dyes and medicines.

Questions

Coke is almost pure:
a) Carbon
b) Oxygen
c) Hydrogen
d) Nitrogen
Coal tar is a:
a) Black thick liquid
b) Gas
c) Solid
d) Colourless liquid
Coal gas is mainly used as:
a) Fuel
b) Fertilizer
c) Medicine
d) Plastic
Coke is used in:
a) Steel manufacturing
b) Cooking
c) Lighting
d) Farming

Case Study 6: Fossil Fuels

Coal, petroleum and natural gas are called fossil fuels. They were formed from the remains of plants and animals millions of years ago. These fuels are limited and should be used carefully.

Questions

Fossil fuels are:
a) Renewable
b) Non-renewable
c) Unlimited
d) Artificial
Fossil fuels formed from:
a) Rocks
b) Dead plants and animals
c) Soil
d) Water
Fossil fuels were formed:
a) Recently
b) Millions of years ago
c) Hundreds of years ago
d) Ten years ago
Which is a fossil fuel?
a) Coal
b) Petroleum
c) Natural gas
d) All of these

Case Study 7: Pollution and Fossil Fuels

Burning fossil fuels releases gases like carbon dioxide and carbon monoxide. These gases cause air pollution and contribute to global warming.

Questions

Burning fossil fuels increases:
a) Oxygen
b) Carbon dioxide
c) Nitrogen
d) Hydrogen
Fossil fuels cause:
a) Air pollution
b) Water purification
c) Soil formation
d) Oxygen increase
Global warming is mainly caused by:
a) Carbon dioxide
b) Oxygen
c) Hydrogen
d) Nitrogen
The best solution is:
a) Burn more fuel
b) Use renewable energy
c) Waste fuel
d) Increase vehicles

Case Study 8: LPG

LPG is widely used as a domestic fuel. It is stored in cylinders and used in kitchens for cooking. It burns easily and produces less smoke.

Questions

LPG stands for:
a) Liquid Petroleum Gas
b) Liquefied Petroleum Gas
c) Limited Petroleum Gas
d) Low Petroleum Gas
LPG is mainly used for:
a) Cooking
b) Road construction
c) Steel making
d) Electricity generation
LPG is stored in:
a) Solid form
b) Liquid form
c) Gas form
d) Powder form
LPG is considered:
a) Polluting fuel
b) Clean fuel
c) Solid fuel
d) Natural mineral

Case Study 9: Conservation of Fossil Fuels

Fossil fuels are limited resources. If we use them carelessly, they may get exhausted. Therefore, we must conserve them by using public transport, saving electricity and using renewable energy.

Questions

Fossil fuels are:
a) Unlimited
b) Limited
c) Artificial
d) Renewable
Conservation means:
a) Wasting resources
b) Saving resources
c) Burning fuels
d) Ignoring fuels
Which helps save fuel?
a) Public transport
b) Saving electricity
c) Renewable energy
d) All of these
Fossil fuel conservation helps:
a) Environment protection
b) Resource saving
c) Pollution reduction
d) All of these

Case Study 10: Petroleum Refining

Crude petroleum is a mixture of many substances. In refineries, it is separated into different fractions like petrol, diesel, kerosene and lubricating oil using fractional distillation.

Questions

Crude petroleum is a:
a) Pure substance
b) Mixture
c) Solid
d) Mineral
The separation method used in refineries is:
a) Filtration
b) Fractional distillation
c) Evaporation
d) Crystallisation
Petrol and diesel are obtained from:
a) Coal
b) Petroleum
c) Natural gas
d) Wood
Refineries are used for:
a) Mining coal
b) Separating petroleum products
c) Growing crops
d) Storing water

Here are 20 Short Answer Questions from Class 8 Science – Chapter: Coal and Petroleum (Minerals and Petroleum) based on the CBSE syllabus.

20 Short Answer Questions

What are fossil fuels?
Fossil fuels are natural fuels formed from the remains of plants and animals buried under the earth millions of years ago. Examples are coal, petroleum and natural gas.
What is coal?
Coal is a hard black fossil fuel mainly made of carbon. It is formed from dead plants buried under the earth for millions of years.
Define carbonisation.
Carbonisation is the slow process of converting dead plants into coal due to high temperature and pressure over millions of years.
What is petroleum?
Petroleum is a dark oily liquid found deep inside the earth between rock layers. It is also called crude oil.
Why is petroleum called black gold?
Petroleum is called black gold because it is very valuable and gives many useful products like petrol, diesel and kerosene.
What are the main products obtained from coal?
The main products obtained from coal are coke, coal tar and coal gas.
What is coke?
Coke is a tough, porous and almost pure form of carbon obtained from coal. It is used in steel manufacturing.
What is coal tar?
Coal tar is a thick black liquid obtained from coal. It contains about 200 useful substances used to make dyes, drugs, perfumes and plastics.
What is coal gas?
Coal gas is a fuel gas obtained during the processing of coal. It is used as a fuel in industries.
What is natural gas?
Natural gas is a fossil fuel mainly composed of methane. It is found along with petroleum deposits underground.
What is LPG?
LPG stands for Liquefied Petroleum Gas. It is a petroleum product used as a fuel for cooking in homes.
What is CNG?
CNG stands for Compressed Natural Gas. It is used as a clean fuel in vehicles.
What is petroleum refining?
Petroleum refining is the process of separating crude petroleum into useful products like petrol, diesel, kerosene and lubricating oil.
What are petrochemicals?
Petrochemicals are chemicals obtained from petroleum used to make plastics, synthetic fibres, detergents and rubber.
Name four products obtained from petroleum.
Four products are:

Petrol
Diesel
Kerosene
Lubricating oil

Why are fossil fuels called non-renewable resources?
They are called non-renewable because they take millions of years to form and cannot be replaced quickly once used.
Why should we conserve fossil fuels?
We should conserve fossil fuels because they are limited and their excessive use causes pollution and global warming.
What is bitumen?
Bitumen is a petroleum product used mainly for road surfacing.
Why is natural gas considered a clean fuel?
Natural gas burns completely and produces less smoke and harmful gases compared to other fossil fuels.
Name two ways to save fossil fuels.

Use public transport or carpooling
Use renewable energy sources like solar energy

Here is an 80 Marks Full Test Paper for Class 8 Science – Chapter: Coal and Petroleum (Minerals and Petroleum) based on the CBSE pattern.

Class 8 Science Test Paper

Chapter: Coal and Petroleum

Time: 2 Hours
Maximum Marks: 80

Section A – MCQs (1 × 20 = 20 Marks)

Coal is mainly composed of
a) Oxygen
b) Carbon
c) Nitrogen
d) Hydrogen
The process of converting dead plants into coal is called
a) Carbonisation
b) Combustion
c) Evaporation
d) Filtration
Petroleum is also known as
a) White gold
b) Black gold
c) Green gold
d) Yellow gold
The main component of natural gas is
a) Methane
b) Nitrogen
c) Oxygen
d) Hydrogen
LPG stands for
a) Liquid Petroleum Gas
b) Liquefied Petroleum Gas
c) Limited Petroleum Gas
d) Low Petroleum Gas
The hardest form of coal is
a) Peat
b) Lignite
c) Anthracite
d) Bituminous
Coke is mainly used in
a) Steel manufacturing
b) Cooking
c) Farming
d) Lighting
Coal tar is a
a) Gas
b) Solid
c) Thick black liquid
d) Colourless liquid
The process of separating petroleum into components is
a) Filtration
b) Fractional distillation
c) Evaporation
d) Sedimentation
Bitumen is used for
a) Cooking
b) Road construction
c) Fertilizers
d) Medicines
Natural gas used in vehicles is called
a) LPG
b) CNG
c) PNG
d) LNG
Fossil fuels include
a) Coal
b) Petroleum
c) Natural gas
d) All of these
Petroleum is found
a) In rivers
b) Under the earth between rock layers
c) On mountains
d) In forests
The cleanest fossil fuel is
a) Coal
b) Petrol
c) Natural gas
d) Diesel
Kerosene is mainly used for
a) Lighting and cooking
b) Steel making
c) Plastic making
d) Fertilizer making
The residue obtained after petroleum refining is
a) Coke
b) Bitumen
c) Coal gas
d) LPG
Coal formation takes
a) Few years
b) Hundreds of years
c) Millions of years
d) One year
Petrochemicals are used to make
a) Plastics
b) Synthetic fibres
c) Detergents
d) All of these
Coal, petroleum and natural gas are called
a) Minerals
b) Fossil fuels
c) Metals
d) Ores
Fossil fuels should be
a) Wasted
b) Conserved
c) Ignored
d) Burned more

Section B – Short Answer Questions

(2 × 10 = 20 Marks)

Define fossil fuels.
What is carbonisation?
What is coke?
Write two uses of coal tar.
What is petroleum?
Name any four products obtained from petroleum.
What is natural gas?
What are petrochemicals?
Why are fossil fuels called non-renewable resources?
Write two ways to conserve fossil fuels.

Section C – Case Study Based Questions

(4 × 5 = 20 Marks)

Case Study 1

Coal was formed millions of years ago from the remains of plants buried under the earth. High temperature and pressure converted them into coal. Coal is used as a fuel and to make coke, coal tar and coal gas.

Questions:

What is the process of coal formation called?
Name two products obtained from coal.
What is coke used for?
Why is coal considered a fossil fuel?

Case Study 2

Petroleum is a dark oily liquid found deep underground. It is refined in petroleum refineries to obtain useful products such as petrol, diesel, kerosene and lubricating oil.

Questions: