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

Organic Chemistry

  Essentially, organic chemistry is the study of many different carbon compounds as carbon can form multiple covalent bonds. The number of organic compounds escalate to approximately 17,000,000 and can form chains, rings, or branches. The simplest organic compounds are composed of Carbon (C) and Hydrogen (H):

 EX.1: Above is an example of an organic compound called ethane.

  Saturated compounds exist with no double or triple bonds. Therefore, compounds with only single bonds are called Alkanes and always end in '-ane'. There are three categories of organic compounds:

  1. Straight Chains

2. Cyclic Chains

3. Aromatics

But today, we will only look at the composition of and naming of the straight chains:

1. Circle the longest continuous chain (this means the longest number of carbons in a row without going back on the chain). This will become the BASE or PARENT chain and can be determined by choosing a prefix and then adding the ending '-ane'.

meth=1 carbon atom

eth=2  carbon atoms

prop=3 "

but=4 "

prop=5 "

hex=6 "

hept=7 "

oct=8 "

non=9 "

dec=10 "

*IN THIS CASE, THE PARENT CHAIN WILL BE HIGHLIGHTED AND WE WILL BE USING A STRUCTURAL DIAGRAM.

                                                                                CH3 CH3

                                                                                  |      |

                                                                      CH3 - CH - CH - CH3

butane

2. Number the base chain in a way so that the side chains (anything not circled as your longest continuous chain), have the lowest possible numbering scheme.

*NUMBERING COULD START FROM LEFT OR RIGHT SIDE IN THIS CASE AS IT MAKES LITTLE DIFFERENCE.

     CH3 CH3

                                                                                  |      |

                                                                      CH3 - CH - CH - CH3

                                                                        1       2      3      4

butane

3. Name each side chain using one of the following prefixes with their '-yl' ending.

methyl=1

ethyl=2

propyl=3

butyl=4

propyl=5

hexyl=6

heptyl=7

octyl=8

nonyl=9

decyl=10

     CH3 CH3

                                                                                  |      |

                                                                      CH3 - CH - CH - CH3

                                                                        1       2      3      4

                                                                           -methyl -methyl butane

4. Give each side chain the appropriate number. If there are more than one of a certain side chain, you would have to number and label accordingly with added prefixes (di for 2, tri for 3, etc.)

     CH3 CH3

                                                                                  |      |

                                                                      CH3 - CH - CH - CH3

                                                                        1       2      3      4

                                                                         2, 3  dimethyl butane

5. When providing the final name for the compound, you must list the side chains alphabetically.

2, 3  dimethyl butane 

For more practice, try out these worksheets: 

http://www.arps.org/users/hs/thompsom/chemcom/unit_3/Naming_Alkanes_Worksheet_1.pdf

& while you're at it, check out this video on naming Alkanes!

http://www.youtube.com/watch?v=KKAD-OOOHxg