April 29, 2024, 12:41:05 AM
Forum Rules: Read This Before Posting


Topic: Systematic names of molecules  (Read 3203 times)

0 Members and 1 Guest are viewing this topic.

Offline FollowTheFez

  • Regular Member
  • ***
  • Posts: 11
  • Mole Snacks: +0/-1
Systematic names of molecules
« on: May 10, 2013, 02:21:57 AM »
Can someone please name the following molecules for me??

I thought Molecule A was:
2-hydroxy-3-Bromo butanoic acid

and I thought molecule B was:
1-hydroxy-2-propyl-cyclohexane.

I only got half marks for each of these and I can't figure out where I went wrong.

Offline sjb

  • Global Moderator
  • Sr. Member
  • ***
  • Posts: 3652
  • Mole Snacks: +222/-42
  • Gender: Male
Re: Systematic names of molecules
« Reply #1 on: May 10, 2013, 03:20:03 AM »
Can someone please name the following molecules for me??

I thought Molecule A was:
2-hydroxy-3-Bromo butanoic acid

and I thought molecule B was:
1-hydroxy-2-propyl-cyclohexane.

I only got half marks for each of these and I can't figure out where I went wrong.

For A CC(C(C(=O)O)Br)O, consider the numbering
For B CCCC1CCCCC1O, is there a simpler name for 1-hydroxycyclohexane

Offline iamback

  • Regular Member
  • ***
  • Posts: 34
  • Mole Snacks: +2/-2
Re: Systematic names of molecules
« Reply #2 on: May 10, 2013, 04:38:04 AM »
I think you got your answer from here: http://openstudy.com/updates/518c8f19e4b062a8d1d9d783

You don't want to learn, you just need answers.

Offline FollowTheFez

  • Regular Member
  • ***
  • Posts: 11
  • Mole Snacks: +0/-1
Re: Systematic names of molecules
« Reply #3 on: May 10, 2013, 04:58:03 AM »
I think you got your answer from here: http://openstudy.com/updates/518c8f19e4b062a8d1d9d783

You don't want to learn, you just need answers.

I don't understand how this answer was reached. This is why I am asking the question. I find that Chemistry forums gives much better explanations when I am confused than openstudy does. Openstudy on the other hand is quicker. If I get something wrong repeatedly, I find the answer and see if I can then work backwards to get the answer. If that fails I look for further help and explanations (which I find are usually better here on Chemistry forums). Please don't question my learning strategies.



I am confused because I always thought the carboxylic acid was named last? Which would make the alcohol group be on the second carbon and the bromo on the third carbon. Why is the carboxylic acid counted first if it is named last? That doesn't seem right.


Offline sjb

  • Global Moderator
  • Sr. Member
  • ***
  • Posts: 3652
  • Mole Snacks: +222/-42
  • Gender: Male
Re: Systematic names of molecules
« Reply #4 on: May 10, 2013, 09:46:02 AM »
I am confused because I always thought the carboxylic acid was named last? Which would make the alcohol group be on the second carbon and the bromo on the third carbon. Why is the carboxylic acid counted first if it is named last? That doesn't seem right.

When you name acids, the carboxyl carbon is usually carbon 1. Just because it appears last in the [English] name does not mean it is lower priority

Offline iamback

  • Regular Member
  • ***
  • Posts: 34
  • Mole Snacks: +2/-2
Re: Systematic names of molecules
« Reply #5 on: May 10, 2013, 11:33:35 AM »
Even if you are correct(which you are not) i.e. 2-hydroxy-3-Bromo butanoic acid, this doesn't make sense, as when there is a choice between which group should be at lower number, the one coming first alphabetically is given the lower number.

This means 2-bromo-3-hydroxy butanoic acid(which is the right answer).

And indeed Carboxylic acid carbon is numbered as 1.

Sponsored Links