[discodermolide]

you have a C-C-C-C-C chain with a C and a C on the third carbon, a C is a methyl group, that is 3,3-dimethylpentane

[joshphillips1977]

Okay sorry I feel stupid, how do you get the 3,3 and the Di?

[discodermolide]

the numbering, count from one end of the chain, the two methyls (Di) are on the third carbon,
3,3-dimethylpentane, di meaning two!

[joshphillips1977]

Okay slap me if I still don't have it. So the carbon on the left is the one substituent and the one on the right is the second not counting the C in the longest chain that puts each one in the Meth group... for example had there been one C on the left and two C to the right it would have been 3-methyl 3-ethylpentane

[discodermolide]

I say again you have a 5 carbon chain.
C-C-C-C-C on the middle carbon there are two substituents two methyl groups.
the longest chain is 5 C atoms i.e. a pentane, on the middle carbon number 3 are two methyl substituents, i,e, dimethyl.
so you have 3,3-dimethylpentane.
No magic, that's it.

[joshphillips1977]

why the two threes?
  C
      |
      C
      |
   C-C-C-C-C-C
      |     |
      C    C
      |
      C
      |
      C
     
Which makes this one 2-propyl 2ethyl 4methylHexane Right? could I say 2,2,4 propylethylmethylHexane?

[discodermolide]

No again find the longest carbon chain

[joshphillips1977]

the longest chain would be six

[discodermolide]

No the longest chain is 8.

Back to the other one, the two "3"s, this is because the two substituents are on the same carbon, carbon number 3, hence 3,3-dimethyl.

[discodermolide]

see picture.

[joshphillips1977]

Okay so them both being on the 3rd carbon makes sense, two substituents both on carbon 3 and both methyl

[discodermolide]

Thats correct.
Now what about the other one, look at the picture I posted.

[joshphillips1977]

see picture.

Oh Snap I get what your saying now... so i am gonna try to answer the second one again and repost...

[joshphillips1977]

see picture.

4,6 dimethyl 4-ethylOctane??

[discodermolide]

Not quite it is 5-ethyl-3,5-dimethyloctane.

the substituents go in alphabetical order.
Then the sum of the numbers must be the lowest, that is in your name the substituents are not in alphabetical order, and the numbers add up to 14.
In my name they are in alphabetical order and the sum is 13.