| saturated |
 ethane C2H6 |
 propane C3H8 |
| unsaturated |
 ethene C2H4 |
 propene C3H6 |
Saturated and unsaturated
When comparing an alkane with the corresponding alkene, the alkane has more hydrogen atoms.
Alkanes are examples of compounds that are referred to as saturated because they contain only single bonds.
Alkenes are examples of compounds that are referred to as unsaturated because they have one or more double bonds.
Other compounds that contain only single bonds may be referred to as saturated.
Other compounds that have double bonds may also be referred to as unsaturated.
As seen at the right saturated hydrocarbons have more hydrogens for a given number of carbons. Alkanes contain the maximum number of hydrogens (2n + 2) for n carbon atoms.
Alkenes contain two fewer hydrogens (2n for n carbons) than the corresponding alkane. Thus it is possible to determine whether or not a hydrocarbon is saturated either from its molecular or structural formula.
When comparing an alkane with the corresponding alkene, the alkane has more hydrogen atoms.
Alkanes are examples of compounds that are referred to as saturated because they contain only single bonds.
Alkenes are examples of compounds that are referred to as unsaturated because they have one or more double bonds.
Other compounds that contain only single bonds may be referred to as saturated.
Other compounds that have double bonds may also be referred to as unsaturated.
Alkenes contain two fewer hydrogens (2n for n carbons) than the corresponding alkane. Thus it is possible to determine whether or not a hydrocarbon is saturated either from its molecular or structural formula.
| number of carbons | prefix in name |
| two | eth |
| three | prop |
| four | but |
| five | pent |
| six | hex |
Naming alkanes and alkenes
The last syllable of the name of an alkane or alkene indicates which of the two families it belongs to.
The last syllable of the name of an alkane or alkene indicates which of the two families it belongs to.
-ane for alkanes
-ene for alkenes
The second syllable of name of the two alkane examples is the same as is the second syllable of the alkene examples.
-ene for alkenes
The second syllable of name of the two alkane examples is the same as is the second syllable of the alkene examples.
The first syllable indicates the number of carbon atoms.
In the examples the first syllable of the hydrocarbons containing two carbons is the same as is the first syllable of the hydrocarbons containing three carbons.