Important Exam Questions – Coal and Petroleum

Class: 8 | Chapter: 5

Very Short Answer Questions (VSA)

1. What are fossil fuels?
2. Name any two fossil fuels.
3. What is coke?
4. Which fuel is known as a clean fuel?
5. Name the natural gas used in homes.
6. What is petroleum also called?
7. What is the main use of coal?
8. Name the solid fossil fuel.

Short Answer Questions (SA)

1. What are fossil fuels? How are they formed?
2. Write any two uses of petroleum.
3. What is natural gas? Write two advantages of natural gas.
4. Explain the process of refining petroleum.
5. Why are fossil fuels called non-renewable resources?
6. Differentiate between renewable and non-renewable resources.

Long Answer Questions (LA)

1. Explain the products obtained from coal and their uses.
2. Describe petroleum refining with the help of a diagram.
3. Why should we conserve fossil fuels? Explain with reasons.
4. Explain the advantages of using natural gas as a fuel.
5. Write a note on alternative fuels and their importance.

 

Conservation of Natural Resources

Conservation of natural resources means using them carefully so that they are available for future generations.

Why Conservation Is Important?

• Natural resources are limited
• They take millions of years to form
• Overuse leads to environmental pollution
• Future generations depend on them

Steps to Conserve Fossil Fuels

• Use public transport
• Switch off vehicles at signals
• Save electricity
• Use energy-efficient appliances

Alternative Fuels

Alternative fuels are sources of energy that can replace fossil fuels and cause less pollution.

Examples of Alternative Fuels

• Solar energy
• Wind energy
• Biogas
• Hydroelectric power

 

Non-Renewable Natural Resources

Non-renewable natural resources are those resources which are present in limited quantity and cannot be replaced once they are exhausted.

Examples of Non-Renewable Resources

• Coal
• Petroleum
• Natural Gas

Why Should We Save Fossil Fuels?

• They take millions of years to form
• They are limited in quantity
• Burning them causes air pollution
• They contribute to global warming

Petrochemicals

Petrochemicals are chemicals obtained from petroleum or natural gas. They are used to manufacture many useful products.

Uses of Petrochemicals

• Making plastics
• Making synthetic fibres
• Making detergents and soaps
• Making medicines and cosmetics

 

Natural Gas

Natural gas is a fossil fuel found deep inside the earth. It is found above petroleum deposits and is the cleanest fossil fuel.

Uses of Natural Gas

• Used as fuel for cooking (PNG and LPG)
• Used in vehicles as CNG
• Used to generate electricity
• Used in industries as fuel

Advantages of Natural Gas

• Burns completely without leaving residue
• Produces very little pollution
• Easy to transport through pipelines

Petroleum Refining

Petroleum refining is the process of separating crude oil into useful components called petroleum products.

Important Petroleum Products

• LPG – Fuel for cooking
• Petrol – Fuel for cars and bikes
• Diesel – Fuel for buses, trucks, and generators
• Kerosene – Fuel for stoves and lamps
• Lubricating Oil – Used in machines
• Bitumen – Used for road surfacing

 

Fossil Fuels

Fossil fuels are fuels formed from the remains of plants and animals that lived millions of years ago. These remains were buried under layers of soil and rocks and slowly changed into fuels due to heat and pressure.

Types of Fossil Fuels

• Coal
• Petroleum
• Natural Gas

Coal

Coal is a hard, black substance found deep under the earth. It is one of the oldest fossil fuels used by humans.

Uses of Coal:

• Used as fuel in thermal power plants to generate electricity
• Used in industries
• Used to make coke, coal tar, and coal gas

Petroleum

Petroleum is a dark, oily liquid found deep inside the earth. It is also known as crude oil.

Petroleum is refined in refineries to obtain useful products like petrol, diesel, kerosene, LPG, and lubricating oil.

 

Class 8 Science – Chapter 5

Coal and Petroleum

🔹 Introduction

Coal and petroleum are very important natural resources. They are used to produce energy, which is required for cooking, transportation, industries, and electricity generation.

🔹 Natural Resources

Natural resources are substances obtained from nature and used by humans for various purposes.

• Exhaustible Natural Resources: Resources that are present in limited quantity and can be exhausted.
  Examples: Coal, Petroleum, Natural Gas
• Inexhaustible Natural Resources: Resources that are available in unlimited quantity.
  Examples: Air, Sunlight, Wind

🔹 Fossil Fuels

Fossil fuels are fuels formed from the remains of dead plants and animals buried under the earth millions of years ago.

Main Fossil Fuels:

• Coal
• Petroleum
• Natural Gas

🔹 Why Fossil Fuels are Limited?

Fossil fuels take millions of years to form. Since they are being used very fast, they may get exhausted in the future. Hence, they are called non-renewable resources.

 

📘 Class 8 Science – Chapter 4
Materials: Metals and Non-Metals

📝 Worksheet (Practice Questions)

Part A: Very Short Answer

1. Name one metal used for making electric wires.
2. Which metal is liquid at room temperature?
3. Name one non-metal used in fertilizers.
4. Which gas is released when metals react with acids?
5. What is the black substance formed on silver?

Part B: Short Answer

1. Write two properties of metals.
2. Why are metals malleable?
3. Write two uses of non-metals.
4. What is corrosion?
5. Why copper is used for making electric wires?

Part C: Long Answer

1. Explain rusting of iron.
2. Write differences between metals and non-metals.
3. Explain methods to prevent rusting.

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✅ FULL ANSWERS (Step-by-Step)

Answers – Part A

1. Copper
2. Mercury
3. Nitrogen
4. Hydrogen gas
5. Silver sulphide

Answers – Part B

1. Two properties of metals:
   • They are good conductors of heat and electricity.
   • They are malleable and ductile.
2. Metals are malleable because metal atoms can slide over each other without breaking.
3. Uses of non-metals:
   • Oxygen is used for breathing.
   • Nitrogen is used in fertilizers.
4. Corrosion is the slow destruction of metals by air, water or chemicals.
5. Copper is used for electric wires because it is a good conductor of electricity and ductile.

Answers – Part C

1. Rusting of Iron:
   Rusting is the process in which iron reacts with oxygen and water to form reddish-brown rust (iron oxide).
   Conditions required: Air and water.
2. Differences between Metals and Non-Metals:
   • Metals are shiny; non-metals are dull.
   • Metals conduct electricity; non-metals do not.
   • Metals are malleable; non-metals are brittle.
3. Methods to Prevent Rusting:
   • Painting
   • Galvanisation
   • Oiling and greasing

CBSE • NCERT • Class 8 Science – Worksheet with Answers