I'm having trouble naming these... which sucks, since I thought I had them all right

Can anyone tell me what I'm doing wrong?

12/7/2007 3:01:39 PM

The first structure is another isomer of butane called isobutane. n-butane would be the normal chain of 4 carbons.

12/7/2007 3:10:06 PM

For several of those, you're not naming the structure, you're just counting carbons.

Read through http://chemistry.boisestate.edu/people/richardbanks/organic/nomenclature/alkanenomenclature1.htm

12/7/2007 3:10:47 PM

On the second one you have a methyl off of both the 2nd and 3rd carbons. Count the longest chain of carbons, which is 4, and this is your parent. 2,3-dimethylbutane

12/7/2007 3:13:45 PM

On the third one, make sure you put the branches in alphabetical order.

12/7/2007 3:17:43 PM

On the 4th one, your longest chain of carbons is 3. The easiest way is to make the propene the parent and have a methyl group off of that. So you'd have 2-methylpropene.

12/7/2007 3:22:41 PM

For the last one, you should always specify where the double bond is in an alkene. This is the cis isomer because both CH3 groups are on the same side. You specify the location of the double bond like this cis-but-2-ene.

12/7/2007 3:29:57 PM

Let me know if I explained them well enough.

12/7/2007 3:30:20 PM

hah, was gonna help in this thread but it looks like it's already been covered.

i <3 organic

12/7/2007 3:43:05 PM

Tenacious, if you have any other questions before your final, post them in here and we'll try to answer.

12/7/2007 4:03:41 PM

tough90zx, I don't need to know for hw or anything & it has been years since I've fathomed looking at organic compounds... however, I've followed everything up until the part with the double bond. If you get a chance, would you mind explaining that again? Thanks!

12/7/2007 4:10:24 PM

If you have an alkene, say for instance, pent-3-ene. The 3 is specifying the carbon on which the double bond starts. So you would have a 5 carbon chain and you would have the double bond between carbons 3 and 4. Doesn't matter from which end you start the numbering.

12/7/2007 4:13:18 PM

When the double bond is not between carbons 1 and 2, you have to worry about cis and trans isomers also.

12/7/2007 4:17:25 PM

Thanks for all the help! I'm at work now, but I'm going to try these again when I get home.

12/7/2007 5:05:24 PM

bttt

1/19/2008 3:08:01 PM