Alkane Nomenclature, Structure, and Properties

Essential Questions

How are alkanes named when given their structures?
How are alkane structures drawn when given their names?
What are the properties of alkanes?

Review Vocabulary

IUPAC (International Union of Pure and Applied Chemistry): An international group that aids communication between chemists by setting rules and standards in areas such as chemical nomenclature, terminology, and standardized methods.

New Vocabulary

Alkane:
Homologous series:
Parent chain:
Substituent group:
Cyclic hydrocarbon:
Cycloalkane:

Alkanes

Alkanes are hydrocarbons that contain only single bonds.
Natural gas and propane are alkanes, commonly used as fuels.

Straight-Chain Alkanes

Methane is the smallest alkane and is used as a fuel and a product of biological processes.
Alkanes have only single bonds between atoms.
Ethane (C2H6) consists of two carbon atoms bonded together with a single bond and six hydrogen atoms.
Propane (C3H8) has three carbon atoms and eight hydrogen atoms. Also known as LP (liquefied propane) gas, it's sold as a fuel for cooking and heating.
Butane (C4H10) has four carbon atoms. It is used as fuel in small lighters and some torches and in the manufacture of synthetic rubber.

Naming Straight-Chain Alkanes

Alkane names end in "-ane."
Alkanes with five or more carbons use a prefix derived from Greek or Latin to indicate the number of carbons (e.g., pentane has five carbons).
Methane, ethane, propane, and butane were named before alkane structures were known and do not have numerical prefixes.

Condensed Structural Formulas

Condensed structural formulas save space by not showing how hydrogen atoms branch off carbon atoms.
The -CH2- unit is a repeating unit in the chain of carbon atoms.
Structural formulas can be further condensed by indicating the number of -CH2- units in parentheses followed by a subscript.

Homologous Series

A series of compounds that differ by a repeating unit is called a homologous series.
A homologous series has a fixed numerical relationship among the numbers of atoms.
For alkanes, the relationship between carbon and hydrogen atoms is expressed as $CnH{2n+2}$ , where $n$ is the number of carbon atoms.
- Example: Heptane (7 carbon atoms) has the formula $C7H{2(7)+2}$ , or $C7H{16}$ .

Vocabulary Word Origin

Homologous comes from the Greek word homologos, meaning agreeing.

Essential Questions

How are alkanes named when given their structures?

How are alkane structures drawn when given their names?

What are the properties of alkanes?

Review Vocabulary

IUPAC (International Union of Pure and Applied Chemistry): An international group that aids communication between chemists by setting rules and standards in areas such as chemical nomenclature, terminology, and standardized methods.

New Vocabulary

Alkane:

Homologous series:

Parent chain:

Substituent group:

Cyclic hydrocarbon:

Cycloalkane:

Alkanes

Alkanes are hydrocarbons that contain only single bonds.

Natural gas and propane are alkanes, commonly used as fuels.

Straight-Chain Alkanes

Methane is the smallest alkane and is used as a fuel and a product of biological processes.

Alkanes have only single bonds between atoms.

Ethane (C2H6) consists of two carbon atoms bonded together with a single bond and six hydrogen atoms.

Propane (C3H8) has three carbon atoms and eight hydrogen atoms. Also known as LP (liquefied propane) gas, it's sold as a fuel for cooking and heating.

Butane (C4H10) has four carbon atoms. It is used as fuel in small lighters and some torches and in the manufacture of synthetic rubber.

Naming Straight-Chain Alkanes

Alkane names end in "-ane."

Alkanes with five or more carbons use a prefix derived from Greek or Latin to indicate the number of carbons (e.g., pentane has five carbons).

Methane, ethane, propane, and butane were named before alkane structures were known and do not have numerical prefixes.

Condensed Structural Formulas

Condensed structural formulas save space by not showing how hydrogen atoms branch off carbon atoms.

The -CH2- unit is a repeating unit in the chain of carbon atoms.

Structural formulas can be further condensed by indicating the number of -CH2- units in parentheses followed by a subscript.

Homologous Series

A series of compounds that differ by a repeating unit is called a homologous series.

A homologous series has a fixed numerical relationship among the numbers of atoms.

For alkanes, the relationship between carbon and hydrogen atoms is expressed as $CnH{2n+2}$ , where $n$ is the number of carbon atoms.Example: Heptane (7 carbon atoms) has the formula $C7H{2(7)+2}$ , or $C7H{16}$ .

Vocabulary Word Origin

Homologous comes from the Greek word homologos, meaning agreeing.

Alkenes

Alkenes are hydrocarbons that contain one or more carbon-carbon double bonds.
They are unsaturated hydrocarbons because they have fewer hydrogen atoms than alkanes with the same number of carbon atoms.
The general formula for alkenes with one double bond is $CnH{2n}$ . Example: Ethene (2 carbon atoms) has the formula $C2H4$ .

Alkynes

Alkynes are hydrocarbons that contain one or more carbon-carbon triple bonds.
They are also unsaturated hydrocarbons.
The general