Coal and Petroleum
Overview
Cars run on petrol, factories on coal, kitchens on LPG — all of these are fossil fuels: energy stored from living organisms that died crores of years ago. This chapter covers the story of coal, petroleum, and natural gas, and why we must conserve them.
Typed Notes
How fossil fuels were formed
Crores of years ago, large forests got buried under the earth (under water and layers of soil). Without air, they could not rot completely. Over millions of years, heat and pressure slowly converted them into carbon-rich coal — this process is called carbonization. Similarly, sea organisms (microbes and plants) also got buried and formed petroleum and natural gas. All of this took crores of years to form — and can be used up in a single use — that is why they are called non-renewable resources — and conservation is essential.
Coal and its products
Coal is a carbon-rich rock that releases energy when burned. It forms in 4 stages: peat (low carbon content) → lignite → bituminous (most commonly used) → anthracite (purest form). Through a process called destructive distillation, coal gives 3 important products: (1) Coke — approximately 98% pure carbon — a very high-energy, smoke-free fuel — used in steel-making (extracting iron from haematite ore) and in industrial heating; (2) Coal tar — a black liquid — used to make synthetic dyes, drugs, explosives, perfumes, and naphthalene balls (used to keep insects away from clothes); (3) Coal gas — used as an industrial fuel for heating purposes.
Petroleum and its products
Petroleum (meaning 'rock oil') is formed from dead sea organisms buried underground — it is a dark, thick liquid. At a refinery, it is heated and separated into different products through fractional distillation: (1) LPG — used in kitchen gas cylinders; (2) Petrol — used in cars and bikes; (3) Diesel — used in trucks, buses, and trains; (4) Kerosene — used in lamps and stoves; (5) Paraffin wax — used in candles and vaseline; (6) Lubricating oil — used as machine oil; (7) Bitumen — the black layer used on roads. One source of petroleum gives us 7 useful products.
CNG and conservation (PCRA)
Natural gas, when compressed, is called CNG (Compressed Natural Gas) — it is a clean fuel: it produces less smoke and less ash — buses and auto-rickshaws in Delhi run on CNG. Conservation tips from PCRA (Petroleum Conservation Research Association): (1) Keep vehicle tyre pressure correct; (2) Drive steadily — avoid sudden braking or acceleration; (3) Switch off the engine at red lights; (4) Use public transport, cycle, or walk; (5) Use CFL or LED bulbs; (6) Set air conditioner temperature to 24–25°C. Every drop saved is a drop saved for the world.
Key Concepts
Revision ke liye ek nazar — exam se pehle yahi padhna hai.
- 01Fossil fuels: formed from living organisms (plants and sea creatures) buried underground crores of years ago — transformed by heat and pressure into coal, petroleum, and natural gas. They will run out one day (non-renewable).
- 02Coal: dead plants (forests) → buried under soil → carbonization → coal (rich in carbon). Types in order: peat → lignite → bituminous → anthracite (the purest form).
- 03Products of coal: Coke (pure carbon — used as fuel in steel-making), Coal tar (used for synthetic dyes, drugs, naphthalene balls), Coal gas (used as industrial fuel).
- 04Petroleum: dead sea organisms → refined at a refinery — products obtained: LPG, petrol, diesel, kerosene, paraffin wax, lubricating oil, bitumen (for roads).
- 05Natural gas: CNG (compressed natural gas) — a clean fuel — used in homes, industries, and vehicles. Conservation tips from PCRA: maintain tyre pressure, drive steadily, switch off engine at red lights, use public transport, use CFL/LED bulbs.
Questions & Solutions
Pehle khud try karo — phir solution kholo. Yahi tariqa topper banata hai.
How are fossil fuels formed? Why are they called non-renewable?
What is coke and where is it used?
Write 5 products of petroleum and their uses.
Why is CNG called a 'clean fuel'?
What are naphthalene balls made from?
Write 3 PCRA tips that help save petrol and diesel.
Fossil fuels = formed from living organisms crores of years ago (through carbonization) — coal, petroleum, natural gas — all non-renewable. Coal → coke (for steel), coal tar (for dyes and naphthalene), coal gas. Petroleum refinery → LPG, petrol, diesel, kerosene, wax, lubricant, bitumen. CNG is a clean fuel. Follow PCRA tips to conserve these resources.
Chapter-end quiz
4 MCQsOption tap karo — turant pata chalega sahi ya galat, explanation ke saath.
Q1.What is the process by which coal is formed called?
Q2.Which product of coal is used in making steel?
Q3.Which substance is used for tarring (surfacing) roads?
Q4.Why is CNG called a clean fuel?
Mark karo — dashboard par progress dikhega.