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IUPAC naming of C1 to C10 compounds is taught in the note for Organic Chemistry. Read it below and look for the section on this topic.

Organic Chemistry

13 min read

Aliphatic hydrocarbons

Organic chemistry is the chemistry of carbon compounds. Carbon atoms form four bonds and can join to each other in chains and rings. A hydrocarbon contains only hydrogen and carbon. Aliphatic hydrocarbons have the carbons in chains (not in a benzene ring). They are the main part of crude oil and natural gas.

Structures of simple hydrocarbonsStructural formulae of methane, ethane, ethene and ethyne. Carbon atoms form four bonds. Methane and ethane have only single bonds and are alkanes. Ethene has one double bond and is an alkene. Ethyne has one triple bond and is an alkyne.CHHHHMethane CH₄alkane, single bondsCCHHHHHHEthane C₂H₆alkaneCCHHHHEthene C₂H₄alkene, one C=CCCHHEthyne C₂H₂alkyne, one C≡C
FamilyGeneral formulaBondsFirst member
AlkanesCₙH₂ₙ₊₂All single bonds (saturated)Methane, CH₄
AlkenesCₙH₂ₙOne C=C double bond (unsaturated)Ethene, C₂H₄
AlkynesCₙH₂ₙ₋₂One C≡C triple bond (unsaturated)Ethyne, C₂H₂

A homologous series is a family of compounds with the same general formula and the same functional group. Each member differs from the next by CH₂. Members have similar chemical properties and a gradual change in physical properties: the boiling point rises as the chain gets longer.

Alcohols

Alcohols contain the hydroxyl group (–OH). Their general formula is CₙH₂ₙ₊₁OH. Methanol is CH₃OH, ethanol is C₂H₅OH and propanol is C₃H₇OH. Ethanol is used as a fuel, solvent and in drinks and disinfectants.

IUPAC naming of C1 to C10 compounds

CarbonsStemAlkaneAlkeneAlcohol
1meth-methane—methanol
2eth-ethaneetheneethanol
3prop-propanepropenepropan-1-ol
4but-butanebut-1-enebutan-1-ol
5pent-pentanepent-1-enepentan-1-ol
6hex-hexanehex-1-enehexan-1-ol
7hept-heptanehept-1-eneheptan-1-ol
8oct-octaneoct-1-eneoctan-1-ol
9non-nonanenon-1-enenonan-1-ol
10dec-decanedec-1-enedecan-1-ol

Isomers are compounds with the same molecular formula but different structures. Butane (C₄H₁₀) has two isomers: butane (a straight chain) and 2-methylpropane (branched). Pentane has three isomers.

Try itFormula and mass of an alkane

Choose the number of carbon atoms in an alkane. Use the general formula CₙH₂ₙ₊₂. (C = 12, H = 1)

Check yourself What is the general formula of the alkenes?
Check yourself How many hydrogen atoms are in a molecule of hexane?
Check yourself Which is the correct name for CH₃CH₂CH₂OH?

Key terms

Hydrocarbon
A compound of carbon and hydrogen only.
Homologous series
A family of compounds with the same functional group and general formula, each differing by CH₂.
Isomers
Compounds with the same molecular formula but different structures.
Saturated
Having only single bonds between carbon atoms.

Summary

  • Alkanes CₙH₂ₙ₊₂ are saturated; alkenes CₙH₂ₙ and alkynes CₙH₂ₙ₋₂ are unsaturated.
  • Alcohols contain –OH and have the formula CₙH₂ₙ₊₁OH.
  • Stems: meth, eth, prop, but, pent, hex, hept, oct, non, dec.
  • Isomers share a formula but have different structures.
Alcohols