Functional Groups

Learning Objectives

  • the grouping of hydrocarbon compounds into families (alkanes, alkenes, alkynes, alcohols, carboxylic acids and non-branched esters) based upon similarities in their physical and chemical properties including general formulas, their representations (structural formulas, condensed formulas, Lewis structures), naming according to IUPAC systematic nomenclature (limited to non-cyclic compounds up to C10, and structural isomers up to C7) and uses based upon properties

Summary Notes

The Hydrocarbons

Molecules that only contain carbon and hydrogen. There are 3 main types...

Alkanes

  • Only contain single bonds.

  • They have the general formula CnH2n+2 .

  • We call alkanes 'saturated' hydrocarbons. This is because all the carbon-carbon bonds are single bonds.

Alkenes

  • Contain a double bond.

  • They have the general formula CnH2n.

  • We call alkenes 'unsaturated' hydrocarbons. This is because all the carbon-carbon bonds are not single bonds.

Alkynes

  • Contain a triple bond.

  • They have the general formula CnH2n-2 .

  • We call alkynes 'unsaturated' hydrocarbons. This is because all the carbon-carbon bonds are not single bonds.

More Functional Groups

Alcohol

  • Molecules that contain an '-OH' group connected to a C.

  • We call this '-OH' group the hydroxyl group.

  • This '-OH' group allows from hydrogen bonds to form between water molecules, making alcohols more easily dissolvable in water.

Carboxylic Acid

  • Molecules that contain an '-COOH' group.

  • We call this '-COOH' group the carboxyl group.

Amine

  • Molecules that contain an '-NH2' group.

  • We call this '-NH2' group the amine group.

Haloalkane

  • Molecules that contain an '-X' group. X stands for any Halogen (Group 17)

  • X is connected to the central C atom and stands in the place of H.

Video to help build your understanding

Practice Material

Teacher's Tip:

Learn this well as this is covered again in Unit 4. Knowing this now makes learning Unit 4 content a much easier experience

If we have one C in a formula, we just write it as C, not C₁

'n' in the formulas stand for any number from on onwards e.g. if you had a alkane with one carbon, it's formula would be C₁H₂(₁)+₂ which is CH₄