Chemistry Unit 2

Unit 2.4: Organic compounds

Naming organic compounds

Functional group – refers to the atom that gives the compound its characteristic reactivity.

Hydrocarbon – is a compound of carbon and hydrogen only.

Alkanes – saturated hydrocarbons

Alkenes – unsaturated hydrocarbons with a C to C double bond

Halogenoalkanes – compounds in which one or hydrogens in an alkane have been replaced by a halogen

Alcohols – compound containing –OH as the functional group

Carboxylic acids – compounds containing –COOH as the functional group

Homologous series - is a series of compounds that have similar properties and the same general formula. They have the same functional group. Their physical properties varies as the Mr varies. E.g. alkenes or alkanes

Naming alkanes, alkenes and alkynes

Alkanes

The alkanes don't contain a functional group and so the branches are numbered from the end that gives the lowest set of position numbers for the branches.

Use the above rules, to see how the names of the alkanes below are built up.

Alkenes and alkynes

The functional group in the alkenes is the carbon-to-carbon double bond.

The functional group in the alkynes is the carbon-to-carbon triple bond.

The basic rules of naming apply.

The position of the double or triple bond is indicated by a number before the '-ene' or '-yne' part of the name.

Naming alcohols, aldehydes and ketones

Alcohols

The functional group in the alcohols is the hydroxyl group (-OH).

Alcohols end in the letters '-ol'.

The basic rules of naming apply.

The position of the hydroxyl functional group is indicated by a number before the '-ol' part of the name.

Alcohols can also be termed primary, secondary or tertiary.

Primary has the -OH on the end of a chain.

Secondary has the -OH on a non-branched carbon atom along the…