Why did i get this wrong- Chemistry

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Darkness_o
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#1
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#1
CH2 CH3
I
CH3 CH2 C=CCH3
I
CH3

I thought the answer was 4-ethyl-3-methylpent-3-ene

but the answer is - 3,4-dimethylhex-3-ene
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summerbirdreads
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#2
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#2
(Original post by Darkness_o)
CH2 CH3
I
CH3 CH2 C=CCH3
I
CH3

I thought the answer was 4-ethyl-3-methylpent-3-ene

but the answer is - 3,4-dimethylhex-3-ene
https://www.savemyexams.co.uk/notes/...-nomenclature/
Try revising.
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Jpw1097
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#3
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#3
(Original post by Darkness_o)
CH2 CH3
I
CH3 CH2 C=CCH3
I
CH3

I thought the answer was 4-ethyl-3-methylpent-3-ene

but the answer is - 3,4-dimethylhex-3-ene
It's not entirely clear what structure you are drawing here, presumably you mean CH3 CH2 HC = CH CH3, you missed a few hydrogen atoms.

The structure that you have drawn is 6-methylhept-2-ene.
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Bk4753
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#4
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#4
Well this was a useless response

OP, Have you written this out correctly? Pretty sure you can't have as C can't connect to 3 Hs and 3 other groups at the same time.
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Jpw1097
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#5
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#5
As Bk4753 has said, what a useless response. I'm not one for doing people's homework for them either, but in this case the OP has had a go and they still don't understand. Maybe we should get rid of all of the study help forums and just say "try revising" instead, what do you think?
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summerbirdreads
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#6
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#6
(Original post by Jpw1097)
As Bk4753 has said, what a useless response. I'm not one for doing people's homework for them either, but in this case the OP has had a go and they still don't understand. Maybe we should get rid of all of the study help forums and just say "try revising" instead, what do you think?
Ok fair enough. My mistake
Last edited by summerbirdreads; 1 month ago
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Darkness_o
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#7
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#7
Sorry, I wrote the compound write but when I posted it, it changed, idk why. But the question is

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scimus63
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#8
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#8
the longest chain must contain the C=C, the longest chain is 6 carbons so hexene
C=C between carbon atoms 3 and 4
methyl group on C3 and C4 so the answer is D

try here it may help a bit

https://www.science-revision.co.uk/A..._branches.html
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Bk4753
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#9
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#9
(Original post by Darkness_o)
Sorry, I wrote the compound write but when I posted it, it changed, idk why. But the question is

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Tricky one but yh they're right. Move the methyl group on the right to the bottom. Then draw the compound as if the "ethyl group" is on the far right as opposed to on top of the carbon on the right. then count backward from the ethyl group. Let me know if you still struggle to see it.
Last edited by Bk4753; 1 month ago
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Darkness_o
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#10
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#10
Thank you
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Bk4753
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#11
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#11
(Original post by Darkness_o)
Thank you
Of course. Hope you get it? And make sure to keep practicing nomenclature. Also, make notes
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_ellielouise
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#12
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#12
(Original post by Darkness_o)
Sorry, I wrote the compound write but when I posted it, it changed, idk why. But the question is

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the reason why it’s 6 carbon and not 5 carbons is because the CH2CH3 can be rotated next to the CCH3 . as molecules have no up or down. so molecules that are always on the last atom can be rotated to be in the longest chain. so now there is 6 carbons hence why it’s “hex”. and it’s “dimethyl” as there are two methyl’s within these chains. it’s always states “3 & 4” as the methyl’s belong to the 3rd and 4th carbon throughout the longest chain
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