[Kaleyrvt]

a)CH3-C=CH-CH2-CH3
          l
        CH3

               CH3
                  l
b) CH3-CH2- C - CH-CH3
                  l      l
               CH3   CH3

                 Cl
                   l
c) CH3 - C = C - CH2 - CH3
             l
           Cl

d) CH3 - CH2 -C = -CH2 - CH3      the 3rd-4th C bond is a triple bond if it does not show right


I am having a hard time figuring this out--any tips on naming??
I tried the 1st one and got: 2-methylpentene
am I close at all?

[DevaDevil]

almost right, what carbon atom has the double bond? That has to be included in the name as well

[constant thinker]

When I go about naming things usually I'll right the prefix of the longest chain. Example is in a the longest C chain is 5, so now you have pent.

Then I check for double and triple bonds, and which carbon there on. If there are only single bonds then I just add -ane (Ex. hexane). If there are double and/or triple bonds you need to have the number of the C with the double or triple bond. Example, for a you have the double bond on the 2nd carbon, therefore now we have pent-2-ene (or I've seen 2-pentene, but I like pent-2-ene better).

Lastly comes all functional and substituent groups. For a there is a methyl group on the 2nd carbon which you've gotten right. Now we have 2-methylpent-2-ene.

It seams you either got lucky or understand the naming, but get confused (I'm betting you understand it  ). Now do the rest. Post the names that you think, and we'll tell you if you're right.

Also, you have to look at the numbering to make sure you have the right values. If you don't know about the whole thing with how to number the carbon chains, look at the wikipedia article on IUPAC nomenclature for organic chemistry.

[Kaleyrvt]

Thanks for the relpies--I read up on some of the websites.. Let me know how I do...I had trouble with  b and c

b)3,3methyl-4pentane
c)2,3chloro-pent-2-ene
d) hex-3-yne


Gosh I hope this is right..
any feedback would be great!

[Yggdrasil]

When you have multiple of a group you need a prefix to show how many of that group are in the molecule.  For example, (b) would be 3,3,4-trimethyl-pentane.  But other than that, good job.

[Kaleyrvt]

THANKS!!!!

and the tri in the 3,3,4-trimethypentane is becasue ???sorry just so I uinderstand completely!

[Yggdrasil]

The tri means that there are three methyl groups.  It doesn't make sense why you need to say 3,3,4-trimethylpentane because 3,3,4-methylpentane just as clearly indicates the presence of three methyl groups, but that's how the IUPAC wants you to do things.

[Kaleyrvt]

ok--hahaha-thank you
have a good one!!!

[constant thinker]

IUPAC naming can be strange at times. I agree with 3,3,4-trimethyl... situation. What's the point of the tri when you have the 3,3,4 which clearly indicates you have 3 methyl groups.