Chapter 4: Carbon and Its Compounds

 

Chapter 4: Carbon and Its Compounds ATOM BOMB 

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Chapter 4: Carbon and Its Compounds

Here are concise notes for CBSE Class 10 Chapter 4: Carbon and Its Compounds:

1. Carbon: The Element of Life

   • Unique Properties:

• Carbon has four valence electrons, allowing it to form four covalent bonds with other atoms.

• It can form long chains, branched chains, and rings, making it versatile in bonding.

• Carbon can bond with itself, leading to the formation of carbon compounds.

• Allotropes of Carbon:

• Diamond: Each carbon atom is bonded to four others in a three-dimensional structure. It is very hard and a good conductor of heat.

• Graphite: Carbon atoms are bonded in layers, with weak forces between layers. It is a good conductor of electricity and is used in pencils.

• Fullerenes: Molecules of carbon in the form of spheres, tubes, or rings.

2. Bonding in Carbon Compounds

   • Covalent Bonding: Carbon atoms form covalent bonds by sharing electrons with other atoms, typically hydrogen, oxygen, nitrogen, etc.

   • Types of Bonds:

     • Single Bond: One pair of electrons is shared between two atoms (e.g., in methane, CH₄).

     • Double Bond: Two pairs of electrons are shared (e.g., in ethene, C₂H₄).

     • Triple Bond: Three pairs of electrons are shared (e.g., in ethyne, C₂H₂).

3. Classification of Carbon Compounds

   • Hydrocarbons: Compounds made of only carbon and hydrogen.

• Alkanes: Saturated hydrocarbons with single bonds (e.g., methane, CH₄).

• Alkenes: Unsaturated hydrocarbons with at least one double bond (e.g., ethene, C₂H₄).

• Alkynes: Unsaturated hydrocarbons with at least one triple bond (e.g., ethyne, C₂H₂).

• Aromatic Compounds: Compounds that contain benzene rings (e.g., benzene, C₆H₆).

• Functional Groups: A group of atoms in a molecule that determines the chemical properties of the compound.

• Alcohols: Contain an -OH group (e.g., ethanol, C₂H₅OH).

• Carboxylic Acids: Contain a -COOH group (e.g., acetic acid, CH₃COOH).

• Aldehydes: Contain a -CHO group (e.g., formaldehyde, HCHO).

• Ketones: Contain a carbonyl group (C=O) between two carbon atoms (e.g., acetone, CH₃COCH₃).

• Esters: Formed from an alcohol and a carboxylic acid (e.g., ethyl acetate, CH₃COOCH₂CH₃).

4. Chemical Reactions of Carbon Compounds

   • Combustion: When carbon compounds react with oxygen, they release energy in the form of heat and light. For example, burning methane produces carbon dioxide and water.

   • Oxidation: Many organic compounds are oxidized to form alcohols, aldehydes, or acids (e.g., oxidation of ethanol forms acetic acid).

   • Addition Reactions: Involves the addition of atoms or groups to a double or triple bond (e.g., hydrogenation of alkenes and alkynes).

5. Important Carbon Compounds

   • Methane (CH₄): A simple alkane, used as a fuel.

   • Ethanol (C₂H₅OH): Alcohol used in alcoholic beverages, solvents, and as a fuel.

   • Acetic Acid (CH₃COOH): A carboxylic acid found in vinegar.

   • Soap and Detergents: Soaps are salts of fatty acids, used for cleaning by forming emulsions with oils and dirt.

6. Isomerism

   • Isomers: Compounds that have the same molecular formula but different structural arrangements. For example, butane (C₄H₁₀) has two isomers: n-butane and isobutane.

   • Types of Isomerism:

     • Structural Isomerism: Different bonding arrangement of atoms.

     • Geometrical Isomerism: Occurs in compounds with double bonds (cis/trans forms).

     • Optical Isomerism: Occurs when a compound has a chiral center, leading to non-superimposable mirror images.

7. Uses of Carbon Compounds

   • Fuels: Carbon compounds like coal, natural gas, and petrol are used as fuels.

   • Medicines: Many drugs are carbon-based (e.g., aspirin, penicillin).

   • Polymers: Long chains of carbon compounds used in plastics (e.g., polyethylene, PVC).

   • Food Additives: Some carbon compounds are used as preservatives and flavor enhancers (e.g., citric acid).