Summary
Organic chemistry studies carbon compounds. Carbon forms four bonds and can join to itself in long chains, branches or rings, with single, double or triple bonds. Hydrocarbons contain only C and H: alkanes (-ane, single bonds, CₙH₂ₙ₊₂), alkenes (-ene, one double bond), alkynes (-yne, triple) and aromatics such as benzene. Names are built from a prefix for the number of carbons (meth-, eth-, prop-, but-, pent-…) and an ending for the family.
Functional groups give each family its properties: alcohols (–OH, -ol), aldehydes (–CHO, -al), ketones (C=O in the middle, -one), carboxylic acids (–COOH), esters (which smell fruity) and amines (–NH₂). Compounds with the same formula and different structure are isomers. The typical reactions are combustion (CO₂ + H₂O), addition to double bonds, esterification and polymerisation, which gives plastics such as polythene.
Key points
- Carbon forms 4 bonds and chains.
- Hydrocarbons: only C and H.
- Alkanes -ane, alkenes -ene, alkynes -yne.
- Prefixes: meth-, eth-, prop-, but-, pent-…
- Alcohol –OH, aldehyde –CHO, ketone C=O, acid –COOH.
- Acid + alcohol → ester + water.
- Isomers: same formula, different structure.
- Combustion: CO₂ + H₂O; addition at double bonds.