Coal and Petroleum (Class 8 Science) Comprehensive Notes & Olympiad Practice Material | Complete Chapter Guide with MCQs and Revision

★ Chapter: Coal and Petroleum – Topic Map




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Part 1: Fossil Fuels Overview & Formation
 Energy Resources: Renewable vs Non-Renewable
 Fossil Fuels: Coal, Petroleum, Natural Gas
 Formation of Coal: Carbonization Process
 Coal Ranks: Peat, Lignite, Bituminous, Anthracite
 Petroleum & Natural Gas Formation (Marine Origin)
 Properties & Importance of Fossil Fuels
 Environmental Issues: Acid Rain, Global Warming, Pollution
 Carbon Cycle & Fossil Fuel Formation

Part 2: Coal Products, Processing & Uses
 Destructive Distillation of Coal (Industrial Process)
 Products: Coke, Coal Tar, Coal Gas
 Structure & Properties of Each Product
 Industrial and Domestic Uses (Metallurgy, Chemical Industry, Fuel)
 Olympiad Insight: Chemical Composition & By-products

Part 3: Petroleum Refining & Natural Gas Utilization




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 Petroleum Composition (Hydrocarbons)
 Refining of Petroleum: Fractional Distillation
 Fractions & Their Uses: Petrol, Diesel, Kerosene, LPG, Paraffin Wax
 Natural Gas: Properties, Uses, Storage, CNG, PNG
 Olympiad Note: Boiling Points vs Hydrocarbon Chain Length

Part 4: Environmental Impact & Conservation
 Air Pollution from Fossil Fuels
 Greenhouse Gases & Global Warming
 Acid Rain: Reactions & Effects
 Oil Spills and Marine Pollution
 Conservation of Fossil Fuels (PCRA Initiatives)
 Alternate Fuels: Biofuels, Hydrogen, Solar, Wind

Part 5: Advanced Concepts & Revision Corner
 Fossil Fuel Chemistry (Hydrocarbons, Alkanes, Alkenes)
 Energy Efficiency: Calorific Value, Unit Conversions
 Sustainable Energy Technologies
 Case Study: Global Fossil Fuel Reserves & Crisis
 Quick Revision Table (Coal vs Petroleum vs Natural Gas)
 Scientist Timeline: Discovery of Coal Gas, Petroleum Drilling
 Fill-in-the-Blanks, Match-the-Following, MCQ Bank (Olympiad level)


Part 1: Fossil Fuels Overview & Formation
▪ Energy Resources: Renewable vs Non-Renewable
 Renewable Resources: Solar, wind, hydro, biomass; can be replenished within a short
period.
 Non-Renewable Resources: Fossil fuels; formed over millions of years, finite in quantity.
 Fossil fuels provide ~80% of global energy, essential for transport, electricity, industries.
💡 Olympiad Tip: Non-renewable = Geological time formation, not human-lifetime replenishable.

▲ Fossil Fuels: Coal, Petroleum, Natural Gas
 Definition: Fuels formed from dead plants and animals buried under sedimentary layers over
geological time.
 Key Composition: Hydrocarbons (C + H), with sulfur, nitrogen, oxygen impurities.
 Major Fossil Fuels:
o Coal: Solid, carbon-rich.
o Petroleum (Crude Oil): Viscous liquid, mix of hydrocarbons.
o Natural Gas: Methane-rich gas.

,  Indirectly store solar energy from ancient photosynthesis.

● Formation of Coal – Carbonization Process
 Around 300 million years ago (Carboniferous Period), large swamp forests existed.
 Dead vegetation buried under soil → high pressure & temperature → slow decomposition.
 Over millions of years: Peat → Lignite → Bituminous → Anthracite.
 Process called Carbonization (conversion of plant matter to coal).
💡 Hinglish Insight: “Socho bade-bade ped-paudhe zameen ke neeche dab gaye. Pressure aur heat
se woh carbon ke solid blocks ban gaye – isko hi carbonization kehte hain.”

★ Coal Ranks (Grades of Coal)
Rank Carbon Moistu Heat Key Uses
% re Value




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Peat ~60% High Low Rarely used as fuel.
Lignite 65–70% Modera Medium Power stations (low cost).
te
Bitumino 75–85% Low High Industry, steam engines.
us
Anthraci 90–95% Very Highest Domestic, metallurgy
te Low (smokeless).
💡 Olympiad Note: Anthracite = Hard coal, highest carbon, least smoke.

■ Petroleum & Natural Gas Formation (Marine Origin)
 Petroleum: Formed from marine plankton and microscopic animals buried under mud,
sand.
 With heat, pressure, and bacteria → converted into kerogen → crude oil.
 Natural Gas: Lighter hydrocarbons form above petroleum layers in reservoir rocks.
 Trapped under impermeable rock layers, extracted via drilling.

▲ Carbon Cycle Overview
 Carbon moves between atmosphere, biosphere, oceans, and lithosphere:
o Plants absorb CO₂ → photosynthesis.
o Animals respire CO₂ back.
o Dead matter → fossil fuels → burning releases CO₂.
 Human use of fossil fuels adds extra CO₂ → climate change.
💡 Hinglish Note: “Jo carbon pedon ne hazaaron saal pehle store kiya, hum ek din mein coal jala ke
release kar dete hain – isi se global warming badhti hai.”

● Properties of Fossil Fuels
 High calorific value (energy per unit mass).
 Release CO₂, SO₂, NOₓ on combustion.
 Non-renewable; reserves may exhaust in ~100–150 years.
 Essential raw material for fertilizers, plastics, and petrochemicals.

■ Environmental Issues
 Air Pollution: Smoke, particulates from coal-fired plants.
 Acid Rain: SO₂ + H₂O → H₂SO₄; NOₓ → HNO₃ → corrodes buildings, harms soil and forests.
 Greenhouse Effect: Extra CO₂ traps heat → rising global temperatures.
 Smog: Photochemical smog in urban areas due to petrol/diesel exhaust.

🧠 Problem-Solving Hints
 MCQs often test coal rank order; remember peat → lignite → bituminous → anthracite.
 “Carbonization” = natural process; “destructive distillation” (in Part 2) = industrial
processing.
 Learn that fossil fuels are carbon sinks – burning them disrupts the natural carbon cycle.
 Practice questions on acid rain reactions and greenhouse gases.

📝 Fill in the Blanks (Part 1)
1. Fossil fuels are formed over ________ of years.
2. The slow process of converting dead vegetation into coal is called ________.