Hydrocarbons and Organic Compounds — O/L Science

Organic chemistry is the study of carbon-containing compounds. Carbon's ability to form four covalent bonds and bond to itself in long chains makes it uniquely suited to form the diverse molecules of life and industry.

Hydrocarbons (only C and H): Alkanes (single bonds, e.g. methane CH₄, ethane C₂H₆ — saturated); Alkenes (one double bond, e.g. ethene C₂H₄ — unsaturated). Alkanes are relatively unreactive (combustion, substitution with halogens); alkenes are more reactive (addition reactions — react with H₂, Cl₂, HBr, H₂O across the double bond).

Functional groups determine chemical behaviour: -OH (alcohols), -COOH (carboxylic acids), -COO- (esters), -NH₂ (amines). Ethanol (C₂H₅OH) — the alcohol in beverages — is produced by fermentation of glucose. Polymers (nylon, polyethylene, rubber) are long-chain carbon compounds with vast industrial applications.