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# gemetric isomers pleeeeeeeeease help anyone! watch

1. How many gemetric isomers are in the compounds in the attachment? Please- how do you work it out?
Attached Images

2. I cant view your attachement, try again and Ill take a look
3. What attachment?
4. lol sorry its there now! i forgot.
5. Don't you look at the number of chiral centers, n, and put i like this: 2^n ?
6. 2 and 3 Geometric isomers rite?
7. (Original post by Owly-woes)
Don't you look at the number of chiral centers, n, and put i like this: 2^n ?
uh, wait... that is for something else.
8. To start with you need to draw out the full structural formulae of these molecules, then you can more clearly see which arrangements are different/the same.
(Just a starter, feel free to ask if this doesn't help )
9. (Original post by martin-jesusfreak)
To start with you need to draw out the full structural formulae of these molecules, then you can more clearly see which arrangements are different/the same.
(Just a starter, feel free to ask if this doesn't help )
Ok, for the first one, I got 2 isomers:

H H H H H H
H-C=C-C=C-C-C-H
H H

The second double bond has 2 different groups attched on both carbons- so 1 group on each, so you can get cis and trans isomers with that- is that correct???
10. Oh man the structure changed when i presses edit...
11. (Original post by Owly-woes)
Don't you look at the number of chiral centers, n, and put i like this: 2^n ?
Is this for optical isomers?
12. Just apply the basic rule: for cis and trans isomers, you need two different functional groups, on either side of the double bond. So if the double bond is at the end of a chain, or in a ring, you wont be getting any isomers there. from that you should be able to work it out quite easily...
13. (Original post by shenzys)
Oh man the structure changed when i presses edit...
Yeah, it will do that.
Try drawing the strucures in paint. Or even better download chemdraw I think there's a free version available.
I think you have the general idea though
14. (Original post by shenzys)
Is this for optical isomers?
Not sure about the english name - I call it diastereomery, I think
15. (Original post by Owly-woes)
Not sure about the english name - I call it diastereomery, I think
yeah diastereoisomerism - stereoisomers which are not enantiomers (often with more than one stereogenic centre), hence the 2n where n is the number of stereogenic centres (minus any meso compounds)
16. dare i ask the meaning of meso compounds?
17. (Original post by Blocker)
dare i ask the meaning of meso compounds?
Compounds that have an internal plane of symmetry with stereocentres but which are not chiral

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