Systematic nomenclature can be used to name organic compounds
Alkanes provide the basis of the naming system
The stem of each name indicates how many carbon atoms are in the longest chain in one molecule of the compound
If there are any side-chains or functional groups present, the position of these groups is indicated by numbering the carbon atoms in the longest chain
The hydrocarbon side-chain is shown in brackets in the structural formula
The side-chain is named by adding ‘-yl’ to the normal alkane stem
Naming conventions for side chains:
If there are multiple of the same alkyl side-chain or functional groups, di- (for two), tri- (for three), or tetra- (for four) is added in front of its name
Adjacent numbers have a comma between them
Numbers are separated from words by a hyphen
If there is more than one type of alkyl side-chain, they are listed in alphabetic order
An aliphatic compound is straight or branched-chain and includes cyclic organic compounds that do not contain a benzene ring
Homologous series in organic chemistry:
A group of organic compounds that have the same functional group
Each successive member differs by CH2
Functional groups determine the physical and chemical properties of molecules
Organic compounds can be classified as aliphatic, alicyclic, or aromatic
Organic compounds can also be described as saturated or unsaturated
Saturated compounds contain single carbon-carbon bonds only
Unsaturated compounds contain at least one carbon-carbon bond that is not single, e.g. C=C or C≡C
Homologous series: group of organic compounds with the same functional group, differing by CH
Alkanes general formula: CnH2n+2
Alkenes general formula: CnH2n
General formulae can predict the chemical formula of any member of the same homologous series
Eicosane: alkane with 20 carbons, formula C20H42
nonapentacontane: alkane with 59 carbons, formula C59H120
Oct-3-ene: alkene with 8 carbons, formula C8H16
Structural isomerism: compounds with the same molecular formula but different structural formulae
Chain isomerism: caused by branching, e.g., pentane and 2,2-dimethylpropane
Positional isomerism: functional group in different positions, e.g., butan-1-ol and butan-2-ol
Functional group isomerism: different functional groups, e.g., butanol and ethoxyethane
Dibromopropane isomers: positional isomerism with two bromine atoms bonded to different carbon atoms
Curly arrows in reaction mechanisms show movement of electrons
Single-headed arrows: movement of one electron in homolytic fission or termination of radicals
Double-headed arrows: movement of a pair of electrons in fission to form positive and negative ions or when lone pair attacks a positive center
Curly arrows in addition reactions, substitution reactions, and elimination reactions
Alkanes are a homologous series made up of saturated hydrocarbons (containing only hydrogen and carbon) joined by sigma (σ) bonds
Alkanes are nonpolar molecules with no partial positive or negative charges
Alkanes do not react with polar reagents
Each carbon in alkanes forms four covalent bonds, resulting in a tetrahedral bonding arrangement with a bond angle of 109.5