L4 - homologous series

What is a homologous series?

A group of chemicals in the same “family” with similar chemical properties, the same functional group, and differing from the next member by one carbon and two hydrogens.

What do all members of a homologous series have in common?

Same functional group, similar chemical properties, and a predictable difference in formula (one C and two H).

What type of bonds are in alkanes and what is their general formula?

All single bonds; general formula is CnH₂n+2.

Give two examples of alkanes.

Methane (CH₄) and ethane (C₂H₆).

What type of bonds are in alkenes and what is their general formula?

At least one double bond; general formula is CnH₂n.

Give two examples of alkenes.

Ethene and propene.

What type of bonds are in alkynes and what is their general formula?

At least one triple bond; general formula is CnH₂n−2.

Give two examples of alkynes.

Ethyne and propyne.

What are isomers?

Compounds with the same chemical formula but different arrangements of atoms.

What happens to the number of possible isomers as the number of carbons increases?

The number of possible structural isomers increases dramatically.

Example: CH₂=CH–CH₂–CH₃ is called what?

1-butene

Example: CH₃–CH=CH–CH₃ is called what?

2-butene

Example: CH₃–C≡C–CH₃ is called what?

2-butyne