Carbon and Covalent Bonding

• Carbon is the 15th most abundant element in the Earth's crust.
• Carbon has an atomic number of 6.
• Carbon has a valency of 4.
• Carbon has an atomic mass of 12u.
• Number of protons equals the number of neutrons, which is 6.
• Electronic arrangement of carbon is 2,4.
• Uses the symbol: C

Covalent Bonds

• Chemical bonds that involve the sharing of electrons to form electron pairs between atoms.
• Three types of covalent bonding exist: single, double, and triple covalent bonds.

Properties of Covalent Compounds

• Low melting and boiling points due to weaker intermolecular forces.
• Generally poor conductors of electricity because they lack charged particles.
• Typically soluble in organic solvents but insoluble in water, with sugar as an exception.

Catenation

• Carbon's ability to form strong covalent bonds with itself to create chains, branches, or rings.

Polymerisation

• Small molecules (monomers) join to form large molecules (polymers).

Isomerism

• Compounds possess the same molecular formula but different structures.

Tetravalency

• Carbon has four valence electrons, forming four covalent bonds, ensuring stability and diverse organic compounds.

Allotropes of Carbon

• Allotropes are various physical forms in which an element can exist.

Diamond

• 3D network structure where each carbon bonds with four others, making it very hard.
• Features four strong covalent bods per carbon making it highlystable.
• Notable for its transparency, high refractive index, and uses in jewelry and abrasives

Graphite

• Graphite has layers of hexagons held by weak forces resulting in softness and a slippery feel.
• Three covalent bonds per carbon, involving delocalized electrons.
• Used in pencils and as a lubricant.

Fullurene

• Composed of a hollow, or cage-like structure with 60 carbons with a soccer ball shape.
• Strong covalent bonds are present in hexagons and pentagons.
• Unique electronic prosperities utilized nanoscience and drugs.

Hydrocarbons

• Hydrocarbon atoms can be replaced by heteroatoms like Cl, S, N, or O, which form functional groups that determine the compound's reactivity and properties.

Common Functional Groups & Formulae

• Alcohol (-OH) ends in -ol (e.g., Ethanol).
• Aldehyde (-CHO) ends in -al (e.g., Ethanal)
• Ketone (-CO-) ends in -one (e.g., Propanone)
• Carboxylic Acid (-COOH) ends in -oic acid (e.g., Ethanoic acid)
• Amine (-NH2) ends in -amine or starts with Amino-

Naming Rules

• Identify the longest carbon chain.
• Number the chain to give the functional group the lowest possible number.
• Functional groups have priority over alkanes, alkenes, and alkynes.
• Utilize a suffix or prefix based on the functional group.

Priority Order (Highest to Lowest)

• COOH > -CHO > -CO > -OH > -NH2.

Homologous Series

• A collection of compounds with the same general formula, differing only in the carbon chain length.
• Homologues share the same general formula.
• Differ by a -CH2 group, with a molecular mass difference of 14 μ.
• Similar chemical properties.
• Gradual change in physical properties.
• Functional group influences properties.

Isomerism

• Compounds with identical molecular formula but different structures.

Chemical Properties of Carbon Compounds

Combustion (Burning)

• Carbon compounds burn in oxygen (O2) to form CO2, H2O, and heat.
• Example: CH4 + 2O2 → CO2 + 2H2O + Heat

Oxidation

• Alcohols are oxidized to acids using KMnO4 or K2Cr2O7.
• Example: CH3CH2OH + [O] → CH3COOH

Addition Reaction

• Unsaturated hydrocarbons (alkenes, alkynes) add H₂ in the presence of Ni/Pd catalyst.
• Example: CH2=CH2 + H2 → CH3-CH3

Substitution Reaction

• Alkanes react with halogens (Cl2, Br2) in the presence of sunlight.
• Example: CH4 + Cl2 → (Sunlight) → CH3Cl + HCl

Chemical Properties of Ethanol and Ethanoic Acid

Ethanol (C2H5OH)

• Ethanol is a liquid at room temperature.
• Ethanol is soluble in water in all proportions.
• Commonly known as alcohol and is the active ingredient in alcoholic drinks.
• Ethanol is a beneficial solvent, used in medicines and tonics.

Reactions of Ethanol

• Ethanol reacts with sodium, producing hydrogen gas and sodium ethoxide.
• Follows the equation: 2Na + 2C2H5OH → 2C2H5O-Na+ + H2

Dehydration of Ethanol to Ethene

• Ethanol when heated with excess concentrated sulphuric acid at 443 K leads to the removal of water (dehydration) and formation of ethene.
• Equation: C2H5OH → CH2=CH2 + H2O (In presence of hot conc. H2SO4)
• Sulphuric acid acts as a dehydrating agent.

Denatured Alcohol

• Ethanol mixed with chemicals to make it unfit for drinking, utilized in industries, cheaper due to tax exemptions.

Ethanoic Acid (CH3COOH)

• Also known as acetic acid and is part of the carboxylic acid group, a 5-8% solution in water is vinegar.

Reactions of Ethanoic Acid

• Esterification: Forms ester with ethanol in concentrated H2SO4.
• Saponification: Esters into salts of carboxylic acids with a base

Structure of Soap/Detergent Molecule

• Both have a Hydrophilic head (Water-attracting, polar) and Hydrophobic tail (Oil-attracting, non-polar)

Cleansing Process (Micelle Formation)

• Soap/detergent allows the hydrophobic tail to attach to grease/dirt, while the hydrophilic head remains in water.
• The molecules form creating a micelle structure, surrounding dirt.
• Dirt trapped, then rinsed away through water,

Hard Water

• Contains high mineral content.
• Does not lather easily with soap.

Soft Water

• Contains low mineral content.
• Lathers easily with soap.