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stereoisomers HELPPPPP

i find them really confusing like how are you meant to distiguish the difference between but-2-ene and but-3-ene how are you meant to know what ethyl groups to use if they would all add up to the general formula for eample
hex-3-ene could be: C2H5 CH3
C=C but in the mark scheme it says
CH3 Ch3


C2h5 H
C=C
H C2H5
For the difference between but-2-ene and but-3-ene, it's according to which carbon number the carbon-carbon double bond is at. E.g. in but-2-ene, the double bond is in the 2nd carbon but in but-3-ene, the double bond is in the 3rd carbon.

What do you mean by which ethyl groups to use? An ethyl group can only be C2H5.
Original post by Namita Gurung
For the difference between but-2-ene and but-3-ene, it's according to which carbon number the carbon-carbon double bond is at. E.g. in but-2-ene, the double bond is in the 2nd carbon but in but-3-ene, the double bond is in the 3rd carbon.

What do you mean by which ethyl groups to use? An ethyl group can only be C2H5.



sorry i meant an alkyl group
Original post by itsastudentyo
i find them really confusing like how are you meant to distiguish the difference between but-2-ene and but-3-ene how are you meant to know what ethyl groups to use if they would all add up to the general formula for eample
hex-3-ene could be: C2H5 CH3
C=C but in the mark scheme it says
CH3 Ch3


C2h5 H
C=C
H C2H5


Still confused about this. Different alkyl groups will cause the molecular formula to be different.
Alkyl groups all have the general formula of CnH2n+1. E.g. a methyl group has the formula CH3, an ethyl group has the formula C2H5, etc.
The markscheme says CH3 CH3 because that's the empirical formula for hex-3-ene. The molecular formula being C6 H12.
Does this make sense? I don't know if I'm waffling lol. Send me a link to the past paper if I talking about something different. :smile:

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