Organic Nomenclature     Part V

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190.
When there are two such radicals attached to a chain,
we do not call them simply "methyl",
but rather we attach the prefix "di",
("Di" means "two".)

The name of such a radical is _______ 


191.                                                                                                   dimethyl
Look at the diagram above.
Number the carbon atoms in both directions.
Apply the numbering rule.
What are the numbers of the carbon atoms
that you will use in the complete name? _____ 
192.                                                                                                  2,3

The name of the compound is ___________ 
193.                                                                                                 2,3-dimethyl pentane

What is the name of this compound ________


194.                                                                                                 propane
This compound still has the three-carbon propane chain,
but something has been substituted for two hydrogens.
What has been substituted? ______

                                                                                       two methyl radicals
The compound is some kind of ________ propane 
                                                                                      dimethyl

Both methyl radicals are attached to the
(what number?) ________ caarbon atom. 
                                                                                        2

Since each radical must be numbered,
the name of the compound is 2,2 ________ 
195.                                                                                      2,2-dimethyl propane

Here is a new diagram.

The longest chain of carbon atoms has
(how many?) _______ atoms. 
                                                                                               five

The presence of five bonded carbon atoms
indicates that this is a  ________ compound 
                                                                                               pentane

There are (how many?) _____ methyl radicals
attached to the chain. 
196.                                                                                         three

"Di" means two.  "Tri" means three.
When two methyl radicals are attached to the same chain,
The name "methyl" changes to __________ 
197.                                                                                        dimethyl

When three methyl radicals are attached to the same chain,
the name "methyl" changes to ______ 
198.                                                                                         trimethyl

In deciding how to number the carbon atom
to which a radical is attached,
you know that you choose the lowest possible number.

When you have more than one attached radical,
whether you start with a carbon atom at the left of the chain
or at the right of the chain, you just keep numbering in the same direction.
In the compound we are studying, we start with the carbon atom at the left
and number left to right.

To what carbon atoms are the methyl radicals attached? _______


199.                                                                                          2,3,4
What is the name of the compound? _________ 
200.                                                                                         2,3,4-trimethyl pentane

Here is the diagram of another compound.
The hydrogen atoms have been left off for the sake of
clarity.  However they are still there in real life and you must
always count bonds to make sure that the diagram is proper.

The longest carbon chain conatins (how many of what?) _______
                                                                                             six carbon atoms

The compound is therefore some kind of __________ 
                                                                                              hexane

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