Alkenes
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The first twelve linear 1-alkenes are shown below, together with their systematic names.
Straight chain 1-alkenes
| Alkene | |
| ethene |  |
| propene |  |
| butene |  |
| pentene |  |
| hexene |  |
| heptene |  |
| octene |  |
| nonene |  |
| decene |  |
| undecene |  |
| dodecene |  |
There is a simple relationship between the number of carbons and hydrogens in these molecules that allow us to easily tell whether a compound is an alkane or an alkene from its formula - an alkane with n carbons will have 2n+2 hydrogens, while an alkene with n carbons will have 2n hydrogens.
For example, C7H16 is an alkane (16 = 2×(7) + 2), while C8H16 is an alkene (16 = 2×8).
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