Drawing line structures

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Shannon Han 2B
Posts: 48
Joined: Fri Sep 26, 2014 2:02 pm

Drawing line structures

Postby Shannon Han 2B » Thu Mar 05, 2015 3:08 pm

When drawing line structures, does it matter what order you put it? For instance, on exercise #2.19, the lowest numbering option is from right to left. However, I first drew the line structure going from left to right if that makes sense. Is my line structure correct even though the one in the solutions does it opposite?

Chem_Mod
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Re: Drawing line structures

Postby Chem_Mod » Thu Mar 05, 2015 5:32 pm

This molecule has an OH functional group which takes the suffix "-ol", and we call this kind of functional group a "suffix group". Whenever you have a suffix group, it MUST take the lowest possible number, and therefore we number the chain from left to right. Having low numbers on the suffix group actually takes precedence over all other numbering rules.

Examples of functional groups that are NOT suffix groups are halogens. So if the OH were Br instead, the correct numbering would be right to left, resulting in lower set of numbers.

Shannon Han 2B
Posts: 48
Joined: Fri Sep 26, 2014 2:02 pm

Re: Drawing line structures

Postby Shannon Han 2B » Fri Mar 06, 2015 9:07 am

Okay that makes sense for the numbering but when you are drawing the line structure does it matter if you start the numbering from the left side of the structure or the right?

Justin Le 2I
Posts: 142
Joined: Fri Sep 26, 2014 2:02 pm

Re: Drawing line structures

Postby Justin Le 2I » Mon Mar 09, 2015 8:33 pm

When you draw it, it doesn't matter because the molecule is identical. Just rotate your paper 180 degrees and you'll get the other view.


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