Alkenes & Alkynes

  Since Carbon can form multiple bonds, it is possible for it to form double and triple bonds with other carbon atoms. When multiple bonds are created, fewer Hydrogens are needed to attach to the Carbon atoms. The naming rules are very similar to that of the naming rules for Alkanes.

 1. The position of the double or triple bonds must always have the lowest numbering scheme and is put in front of a parent chain. They take priority over the side chains.

CH3

|

CH2

|

                                                             CH2 = CH2 - CH2 - CH3

                                                               1        2        3       4

3 ethyl 1 butene

CH3

|

                                                                        CH3 - C - CH2 - CH = CH

|

CH3

                                                                          5     4       3       2       1

4, 4 diethyl 1 pentyne  

2. Double bonds end in '-ene' and are known as Alkenes. In diagrams, they are represented by a double line.

3. Triple bonds end in '-yne' and are known as Alkynes.In diagrams, they are represented by a triple line.

Check out this PDF for more practice problems:

http://www.mouatonline.com/Teachers/BHutchinson/Chemistry/Chem11/Unit%207/PS%207.2%20-%20Alkenes%20etc%28ans%29.pdf

Try these videos out too and learn more about Alkenes & Alkynes!

http://www.youtube.com/watch?v=KWv5PaoHwPA

http://www.youtube.com/watch?v=TBQjbGcUcUw&feature=related