🔬 Science and Technology

💎 Carbon: An Important Element

Explore carbon allotropes, coal formation, hydrocarbons, CO₂ & methane properties, biogas production, and the fascinating world of carbon compounds.

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Study Guide — Key Q&A

Carbon & Covalent Compounds

1What is the uniqueness of carbon?

Carbon has atomic number 6, electronic configuration 2, 4, and valency 4. It can form 4 covalent bonds and exhibits catenation — the ability to form long chains by bonding with other carbon atoms.

2What are the properties of covalent compounds?

Covalent compounds have low melting/boiling points, are poor conductors of heat and electricity, are insoluble in water but soluble in organic solvents like kerosene and cooking oil.

Allotropes of Carbon

3Compare diamond and graphite structures.

Diamond: Each carbon bonds with 4 others in a rigid 3D tetrahedral structure → hardest natural substance, poor conductor. Graphite: Each carbon bonds with 3 others in hexagonal layers that slide → soft, good conductor due to free electrons between layers.

4What is fullerene and who discovered it?

Fullerene is a hollow spherical cage-like allotrope of carbon discovered in 1985 by Harry Kroto, Robert Curl, and Richard Smalley. C₆₀ has 12 pentagonal and 20 hexagonal faces resembling a football.

Coal & Non-Crystalline Carbon

5What are the four types of coal in order of carbon content?

Peat (<60%) → Lignite (60-70%) → Bituminous (70-90%) → Anthracite (~95%). Anthracite is the purest form of coal.

6What are the uses of coke?

Coke is used as a domestic and industrial fuel, as a reducing agent in metallurgy, and to produce water gas (CO + H₂) and producer gas (CO + H₂ + CO₂ + N₂).

CO₂, Methane & Biogas

7How does a CO₂ fire extinguisher work?

It contains NaHCO₃ powder and H₂SO₄ in a glass capsule. When activated: 2NaHCO₃ + H₂SO₄ → Na₂SO₄ + 2H₂O + 2CO₂↑. CO₂ is heavier than air and smothers the fire by cutting off oxygen.

8Explain biogas production.

Biogas (55-60% CH₄) is produced by anaerobic decomposition of organic matter in two stages: 1) Microbes break down complex organics into acids. 2) Methanogenic bacteria convert acids to methane: CH₃COOH → CH₄ + CO₂.

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Glossary

Covalent Bond

A bond formed by sharing of electron pairs between atoms.

Allotropes

Different structural forms of the same element (e.g., diamond, graphite, fullerene).

Catenation

The ability of carbon to form long chains by bonding with other carbon atoms.

Tetrahedral

A 3D geometric shape with 4 faces, as seen in diamond's structure.

Saturated Hydrocarbon

Hydrocarbon with only single C-C bonds (e.g., methane, ethane).

Unsaturated Hydrocarbon

Hydrocarbon with double or triple C-C bonds (e.g., ethene, ethyne).

Sublimation

Direct conversion of solid to gas without passing through the liquid state.

Dry Ice

Solid carbon dioxide (CO₂) that sublimates at -78.5°C.

Biogas

Fuel gas containing 55-60% methane, produced by anaerobic decomposition.

Methanogenic Bacteria

Bacteria that produce methane from organic acids in anaerobic conditions.

Anthracite

Purest form of coal with ~95% carbon content.

Fullerene

Hollow spherical cage-like allotrope of carbon (e.g., C₆₀).

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Practice Quizzes

Test your knowledge with multiple quiz types — 105 questions total:

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Textbook Chapter

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💎 Carbon: An Important Element

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Flashcards (40 Cards)

Study Guide — Key Q&A

Glossary

Practice Quizzes

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