Class 8 Coal and Petroleum - Q and A

on
Coal and Petroleum - Class 8 CBSE

Coal and Petroleum

Class 8 CBSE - Important Questions & Answers

Coal and Petroleum

Short Answer Questions (SAQs)

  1. Q1. What are minerals?
    Minerals are useful natural chemicals found in the lithosphere.
  2. Q2. Define fractional distillation.
    Fractional distillation is the process of separating petroleum into useful products by heating it in a tall fractionating tower.
  3. Q3. What is off-shore drilling?
    Off-shore drilling is the process of extracting petroleum from beneath the sea-bed.
  4. Q4. What is meant by "energy crisis"?
    Energy crisis means shortage of energy sources due to their rapid consumption.
  5. Q5. Name two inexhaustible resources.
    Sunlight and air.
  6. Q6. Give two examples of exhaustible resources.
    Coal and petroleum.
  7. Q7. What are fossil fuels?
    Fuels like coal, petroleum, and natural gas formed from dead plants and animals over millions of years under high temperature, high pressure, and absence of air.
  8. Q8. Why can't fossil fuels be made in a laboratory?
    Because they take millions of years to form naturally and require natural geological processes.
  9. Q9. Name two states in India rich in coal deposits.
    Jharkhand and West Bengal.
  10. Q10. What is carbonisation?
    Carbonisation is the slow process of changing plant material into coal under high temperature, high pressure, and absence of air.
  11. Q11. Which type of coal has the lowest carbon content?
    Peat.
  12. Q12. Which type of coal has the highest calorific value?
    Anthracite.
  13. Q13. Name the products of destructive distillation of coal.
    Coke, coal tar, coal gas, and ammoniacal liquor.
  14. Q14. What is water gas made of?
    Carbon monoxide (CO) and hydrogen (H₂).
  15. Q15. Name two uses of coke.
    Used as a fuel and as a reducing agent in metallurgy.
  16. Q16. From which coal product are naphthalene balls obtained?
    From coal tar.
  17. Q17. What does petroleum mean?
    Petroleum means "oil of rocks" (petro = rock, oleum = oil).
  18. Q18. What is crude oil?
    Crude oil is unrefined petroleum that cannot be used directly and needs refining.
  19. Q19. Name two locations in India where petroleum is found.
    Bombay High (offshore) and Ankleshwar (Gujarat).
  20. Q20. Which gas forms the main component of natural gas?
    Methane.
  21. Q21. What is CNG?
    CNG stands for Compressed Natural Gas, natural gas stored under high pressure for use as fuel.
  22. Q22. Why is CNG called a clean fuel?
    Because it burns without producing ash or smoke.
  23. Q23. Name two uses of natural gas.
    Used as fuel and for making fertilizers like urea.
  24. Q24. State one environmental problem caused by burning coal.
    It releases carbon dioxide which causes global warming.
  25. Q25. Name any two petroleum products not used as fuel.
    Lubricating oil and paraffin wax.

Long Answer Questions (LAQs) – Point-wise

  1. Q1. Explain the types of natural resources with examples.
    1. Inexhaustible resources – Unlimited in nature, will not run out (e.g. sunlight, air, water).
    2. Exhaustible resources – Limited in nature, can finish if overused (e.g. coal, petroleum, natural gas, forests, minerals, wildlife).
  2. Q2. Describe the formation and types of coal.
    1. Formation – Carbonisation:
    1. Millions of years ago, dead plants were buried under soil.
    2. High temperature, high pressure, and no air converted them into coal over time.
    3. This slow change is called carbonisation.
    2. Types of Coal (in increasing carbon content):
    1. Peat (~30% carbon) – Low grade, high moisture, poor fuel.
    2. Lignite (~38% carbon) – Brown, better than peat.
    3. Bituminous (~65% carbon) – Black, good heating value, industrial use.
    4. Anthracite (~90% carbon) – Hard, shiny, burns clean with high heat output.
  3. Q3. State the uses of coal and its products.
    1. Coal itself: Fuel, electricity generation, metal extraction, making synthetic petrol and gas.
    2. Coke: Fuel, reducing agent, production of water gas and producer gas, making carbides.
    3. Coal Tar: Source of dyes, drugs, perfumes, plastics, explosives.
    4. Coal Gas: Heating in industries, creating reducing atmosphere.
    5. Ammoniacal Liquor: For making fertilizers.
  4. Q4. Explain destructive distillation of coal with products and uses.
    1. Process: Heating coal without air at 1000–1400°C.
    2. Main Products & Uses:
    1. Coke: 98% carbon, used in metallurgy, making fuel gases, carbides.
    2. Coal Tar: Thick black liquid, source of many chemicals.
    3. Coal Gas: Earlier for street lighting, now for heating and metallurgy.
    4. Ammoniacal Liquor: For fertilizers.
  5. Q5. Explain the formation and mining of petroleum.
    1. Formation:
    1. Dead marine organisms buried under sand/clay.
    2. Millions of years → high temperature, high pressure, and bacterial action → petroleum forms in porous rocks, trapped below impermeable rocks.
    3. Natural gas covers petroleum layer.
    2. Mining:
    1. Drill holes and insert pipes to reach petroleum.
    2. Oil gushes out due to gas pressure, later pumped.
    3. Depth: few hundred m to 2–3 km.
  6. Q6. What is fractional distillation of petroleum? Name its fractions and uses.
    1. Definition: Process of heating crude oil in a steel fractionating tower; vapours condense at different heights based on boiling points.
    2. Fractions & Uses:
      1. LPG – Cooking fuel
      2. Petrol – Vehicles, dry cleaning
      3. Kerosene – Domestic fuel, lamps
      4. Diesel – Transport, pumps
      5. Fuel oil – Industrial boilers
      6. Lubricating oil – Machines
      7. Paraffin wax – Candles, polish
      8. Asphalt – Roads
  7. Q7. Give the uses of natural gas.
    1. Domestic and industrial fuel
    2. Producing hydrogen for making ammonia → urea fertilizers
    3. Making carbon black for tyres and rubber goods
    4. Raw material for petrochemicals
  8. Q8. List the harmful effects of excessive use of coal and petroleum.
    1. Energy crisis – Reserves may end in about 50 years (petroleum) and 150–200 years (coal)
    2. Earth changes – Land collapse, minor quakes
    3. Pollution:
    1. CO₂: Global warming
    2. CO: Poisonous gas causing suffocation
    3. SOₓ & NOₓ: Cause acid rain, damage marble, metals, health
  9. Q9. State any five tips given by PCRA to save petroleum.
    1. Drive at moderate speed
    2. Avoid unnecessary accelerator pressing
    3. Switch off engine at long waits
    4. Keep tyres at correct pressure
    5. Service vehicles regularly

Higher Thinking / Mixed Conceptual Qs

  1. Q1. Why is anthracite considered the best type of coal?
    Because it has highest carbon content (~90%), burns clean, and gives maximum heat.
  2. Q2. Why is fractional distillation important for petroleum?
    Because crude oil contains many useful substances that have different uses and are separated by boiling points in this process.
  3. Q3. Explain why we should use CNG in place of petrol/diesel wherever possible.
    CNG burns clean without harmful smoke, produces only CO₂ and water, reduces air pollution, and saves petroleum.
  4. Q4. Give reason: Fossil fuels are called non-renewable sources of energy.
    They take millions of years to form and cannot be renewed quickly once used up.

Class 8 Science - Chemistry (CBSE) | Coal and Petroleum

Comments

Post a Comment