Class 8 Science Chapter 3 Important Question Answers - Coal and Petroleum

Q1: What are natural resources, and why are they important for human survival?
Ans: Natural resources are materials obtained from nature that are essential for human survival and development. They are important because they provide us with the necessary materials for our basic needs.

Q2: Define inexhaustible natural resources and provide examples.
Ans: Inexhaustible natural resources are those that exist in unlimited quantities in nature and are not likely to be exhausted by human activities. Examples include sunlight and air.

Q3: Explain exhaustible natural resources and provide examples.
Ans: Exhaustible natural resources are limited in quantity and can be depleted by human activities. Examples include forests, wildlife, minerals, coal, petroleum, and natural gas.

Q4: How was coal formed, and why is it considered a fossil fuel?
Ans: Coal was formed from the remains of dense forests that got buried under soil about 300 million years ago. The high pressure and temperature over time converted the dead vegetation into coal, a process called carbonization. Coal is considered a fossil fuel because it originated from the remains of ancient living organisms.

Q5: What are the main uses of coal in our daily lives and industries?
Ans: Coal is used as a fuel for cooking, in thermal power plants for electricity generation, and as a fuel in various industries.

Q6: What are the byproducts obtained from coal processing, and how are they used?
Ans: Byproducts of coal processing include coke, coal tar, and coal gas. Coke is used in steel manufacturing, coal tar is used in various industries, and coal gas is used as a fuel.

Q7: Explain the historical significance of coal gas in London and New York.
Ans: Coal gas was used for street lighting in London in 1810 and in New York around 1820. It was later used as a source of heat. This marked an important advancement in lighting and heating technology.

Q8: How is petroleum formed, and where is it found in India?
Ans: Petroleum is formed from the remains of marine organisms that settled at the bottom of the sea, got covered with layers of sand and clay, and underwent transformation due to high pressure and temperature over millions of years. In India, petroleum is found in Assam, Gujarat, Mumbai High, and river basins of Godavari and Krishna.

Q9: Describe the refining process of petroleum and its various constituents.
Ans: Refining is the process of separating various constituents/fractions of petroleum. These include petroleum gas, petrol, diesel, lubricating oil, paraffin wax, etc.

Q10: What are petrochemicals, and how are they used in everyday life and industry?
Ans: Petrochemicals are substances derived from petroleum and natural gas, used in the manufacture of detergents, fibers, plastics, and other products. Hydrogen gas obtained from natural gas is used in fertilizer production.

Q11: Why is petroleum often referred to as "black gold"?
Ans: Petroleum is called "black gold" because of its great commercial importance due to its widespread use in various industries and as a fuel source.

Q12: Why is natural gas considered a cleaner fuel, and how is it transported?
Ans: Natural gas is considered cleaner because it produces fewer pollutants when burned. It is transported under high pressure as compressed natural gas (CNG) and can be used directly in homes and factories through pipelines.

Q13: Where in India is natural gas found, and how is it used?
Ans: Natural gas is found in Tripura, Rajasthan, Maharashtra, and the Krishna Godavari delta. It is used as a fuel for power generation, transport vehicles, and in the manufacture of chemicals and fertilizers.

Q14: Explain the importance of conserving fossil fuels like coal and petroleum.
Ans: Fossil fuels take millions of years to form but can be depleted relatively quickly by human activity. Their use is linked to air pollution and global warming, making conservation essential for a better environment and long-term availability.

Q15: How does the Petroleum Conservation Research Association (PCRA) advise people to save petrol/diesel while driving?
Ans: PCRA advises people to save petrol/diesel by driving at a constant and moderate speed, switching off the engine at traffic lights or when waiting, ensuring correct tire pressure, and maintaining their vehicles regularly to improve fuel efficiency.