Please help with IUPAC!?

Question

Pls help, I have no idea how to tell the suffix. For example, http://upload.wikimedia.org/wikipedia/ja/6/6c/2,2-dimethylpropane.PNG
how do I know whether it's 2-dimethylpropane OR 2-dimethylpropene? Which hydrogens should I count to derive the answer? Best ans gets 10 points, thanks a lot :)

Answer 1

2 - dimethyl propane is the alkane group; this means that the main carbon chain (3 carbons, as it is propane) has single bonds between each carbon. alkanes have the suffix -ane.



2 - dimethyl propene on the other hand, is of the alkene group; this means that there is one double bond between two or more carbons in the main chain. alkenes have the suffix -ene



as you can see in the diagram, there are only single bonds between ALL the carbons, and therefore it must be 2-dimethyl propane.

Answer 2

It's 2,2-dimethylpropane (all substituent groups have to have a number) - though just calling it dimethylpropane is fine because the methyl groups can't be anywhere other than on C-2.

It's -ane rather than -ene because all the bonds are single bonds - there would have to be a double bond for it to be an -ene.

Answer 3

There are no double bonds, so it would be 2,2-dimethylpropane. If one of the methyl groups was CH2 instead, it would be 2,2-dimethylpropene.



When naming, count the longest chain of Carbons. In this case, it wouldn't matter, because every chain would be CH3-C-CH3.

Answer 4

You don't need to count hydrogens, you just look at the bonds between carbons.

If there are only single bonds it is an alkane (like in the link you have there are only single bonds so propane is right)

If there is one or more double bonds it would be an alkene (propene).

And if there is one or more triple bonds it would be an alkyne (propyne).

Answer 5

Its 2-dimethylpropane of course .Its propane because it has all single bonds.Something ends with -ene when it has a double bond. this has no double bonds.Hope you are satisfied

Answer 6

the answer is 2,2 di-methyl propane



you have to first choose the longest chain then number the carbon atoms giving first priority to bonds such as double or triple then to functional groups such as OH and last to attachments such as CH3 or C2H2, ETC.



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