Chemistry
Organic chemistry — the basics — quick study summary
Organic chemistry is the chemistry of carbon compounds. Carbon forms 4 covalent bonds and chains/branches/rings of almost any length, which is why life is built from it. Alkanes (single bonds) are saturated; alkenes (double bonds) and alkynes (triple bonds) are unsaturated. Functional groups (–OH alcohol, –COOH carboxylic acid, –NH₂ amine, etc.) determine reactivity. IUPAC naming picks the longest carbon chain as the parent and labels branches and groups.
Key points
- Carbon forms 4 bonds — chains, branches, rings of any size
- Alkanes (CₙH₂ₙ₊₂) saturated; alkenes (C=C) and alkynes (C≡C) unsaturated
- Functional groups: –OH, –COOH, –CHO, –NH₂, –C=O, halogens
- IUPAC name: longest chain → suffix (-ane/-ene/-yne) → number substituents
- Isomers: same formula, different structures — gives different properties
Practice quiz
Click each question to reveal the answer.
1. What is the general formula of an alkane?
- CₙHₙ
- CₙH₂ₙ
- CₙH₂ₙ₊₂
- CₙH₂ₙ₋₂
Answer: CₙH₂ₙ₊₂
Alkanes are fully saturated chains, so each carbon has the maximum number of hydrogens — CₙH₂ₙ₊₂.
2. Which functional group is in ethanol, CH₃CH₂OH?
Answer: Hydroxyl (–OH), making it an alcohol
The –OH group attached to a carbon defines the alcohol family. Ethanol's reactivity (acidic H, polar) comes from this group.
3. How many bonds does carbon form in stable organic compounds?
Answer: Four
Carbon has 4 valence electrons and forms 4 covalent bonds — this is why it can build such varied structures.
Last reviewed: May 2026