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Topic: IUPAC name, kekule and skeletal forms  (Read 4436 times)

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Offline leyus

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IUPAC name, kekule and skeletal forms
« on: November 13, 2011, 12:22:52 PM »
Hello

This is my homework, I already have done 1 and 2 and I found them easy. But I have problem with few others and it is extremely important as it is 5% of my mark.


3. I think A is 3-oxyhexane B) 3-bromo6,7oxypentane I will be grateful if you could check it

About 3 and 4 if you will be able to point me to some good website of pdf file explaining it I will be grateful, because I did number 4 but I am very unsure is it correct (as with 3). I know that on your forum there is post about 4A but pictures in it do not work. 

5 and 6 we will cover in next few lectures so I have no idea how to do it, but I expect they will teach me soon so I am not so worried, I however done some research on number 6 and I think it might be polyethylene and nylon, am I right?

It is uni homework but it is not compulsory  module, I choose it and now I struggle with it, I posted it here because this module suppose to let us help with our chemistry up to high school level and it won't be really related to my further studies (I'm doing mechanical engineering) but I would still prefer to learn it and have it right.

Thanks

Offline fledarmus

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Re: IUPAC name, kekule and skeletal forms
« Reply #1 on: November 14, 2011, 08:09:32 AM »
No, 3) is wrong too.

http://en.wikipedia.org/wiki/IUPAC_nomenclature_of_organic_chemistry might help you some for both 3) and 4). You first need to recognize what the functional groups are in your molecule - that will determine how they are named.

your answer for 6 is one of thousands of possible correct answers  :D.

Offline leyus

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Re: IUPAC name, kekule and skeletal forms
« Reply #2 on: November 15, 2011, 08:57:09 AM »
I read taht and I think I can understand more so I think it will be:
A) 3-onehexane
B) 1-one,1-hydroxy4-bromohexane

I hope I got it right this time. I will later post my drawings from number 4 because I am afraid that if I had 3 wrong then maybe those were wrong as well, will look at them again and post how I think they should look.  Thanks for the link.

Offline fledarmus

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Re: IUPAC name, kekule and skeletal forms
« Reply #3 on: November 15, 2011, 12:27:24 PM »
I'm afraid you've got two different different problems - first, you are having trouble recognizing functional groups, and second, you are having trouble with the structure behind the IUPAC system. Are you just beginning your organic course? I had assumed from the title of your paper (mid-term assessment) that you had already seen most of this, but maybe I got the wrong impression?

Anyway, the suffix "-one" that you are using is the suffix for a ketone, and neither of these two compounds contains a ketone. If you look at the table of functional groups on that organic nomenclature page, you will note that a functional group has the structure
 

That is, a carbonyl (carbon atom with a double bond to oxygen), attached to carbon atoms on both sides (R groups by definition are attached through a carbon atom). Your problem 3a does not have a carbonyl group at all, your problem 3b has a carbonyl attached to a hydroxy group on one side, which make up a different functional group (which you should be able to recognize - or find on the table).

Second, the "-one" is a suffix - it comes at the end of the word. The major functional group in your compound, in the IUPAC nomenclature, is identified by the suffix. So even if your 3a was actually a ketone (which it is not) that had a 6 carbon chain with the double-bond to oxygen on the third carbon, it would have been 3-hexanone, not 3-onehexane.

Incidentally, I only recommended the wiki page as a way to jog your memory on IUPAC nomenclature. It has been abbreviated to the point where it is useful as a reminder, but would be very difficult to use as a primer on nomenclature. If you have never seen this nomenclature before, it would be much more useful to find a college textbook on organic chemistry and get a more detailed explanation with more illuminating examples to work your way through.

Offline leyus

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Re: IUPAC name, kekule and skeletal forms
« Reply #4 on: November 17, 2011, 02:28:01 PM »
It's a foundation chemistry and organic chemistry is part of it and it was just started. Actually I found out today that I had no idea how to do it because we didn't cover it yet. I will try one more time today, I done as you recommended and started reading book about it, course is just going too fast for me and as I can manage to do some things (1 and 2 I found relatively easy) some are still difficult. We more or less covered theory part about naming those today however we had no tutorial on that lecture yet so hopefully we will get practical part on naming them soon.

Offline leyus

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Re: IUPAC name, kekule and skeletal forms
« Reply #5 on: November 17, 2011, 05:41:21 PM »
3A) dippropaneone
3B) 4-bromohexaneoic acid

4:


5. esters

I hope this time it's all correct, anyway during weekend I will spend some quality time with a book because after this lecture I do have idea how this should be done but I'm not confident about my ideas.

Offline leyus

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Re: IUPAC name, kekule and skeletal forms
« Reply #6 on: November 18, 2011, 07:44:16 AM »
We had turtorial today and i read about it yesterday and it helped so, 3a) is probably dipropylether and at 4a) there is one more carbon at the right end which I forgot to draw. Thanks for all the help, I gave lecturer my homework today so if those answers are wrong then it doesn't matter because it's gone. Thanks again mate I gave you a mole snack  :)

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