Streoisomerism. pass paper mistake or just me? Watch

flux capacitor
Badges: 10
Rep:
?
#1
Report Thread starter 1 year ago
#1
How many stereoisomers?

Mark scheme says 4. I only see 2.

one of the double bonds is surrounded by 3 H so you dont get an isomer?

Have I drawn it right?

thanks
Attached files
0
reply
EdexcelAreIdiots
Badges: 9
Rep:
?
#2
Report 1 year ago
#2
(Original post by flux capacitor)
How many stereoisomers?

Mark scheme says 4. I only see 2.

one of the double bonds is surrounded by 3 H so you dont get an isomer?

Have I drawn it right?

thanks

2x E/Z isomers

2x Optical isomers (don't worry about this if you're currently on AS )
0
reply
flux capacitor
Badges: 10
Rep:
?
#3
Report Thread starter 1 year ago
#3
(Original post by EdexcelAreIdiots)
2x E/Z isomers

2x Optical isomers (don't worry about this if you're currently on AS )
wow! thanks for the reply. let me see if i can spot them now.
0
reply
flux capacitor
Badges: 10
Rep:
?
#4
Report Thread starter 1 year ago
#4
Nope cant see it.

Im looking at the first double bond, I see it surrounded by 3 different grps.
1) H
2) CH3
3) H
4) C4OH7

So we have 1 grp in common on the C atoms connected to the double bond (The H) so we can use cis/tran notation if we like.
That's all im seeing on the first double bond.

The second double bond
1) H
2) H
3) H
4) C5H9O

There are 3 groups the same - so we cant get any isomerism around that double bond?

Where am I going wrong?

for optical isomers we need 4 different grps no? OH i think i have seen my mistake now. it not to do with the double bond.

thanks
0
reply
flux capacitor
Badges: 10
Rep:
?
#5
Report Thread starter 1 year ago
#5
ok the carbon connected to the OH is a chiral centre? is that what i was missing?
0
reply
EdexcelAreIdiots
Badges: 9
Rep:
?
#6
Report 1 year ago
#6
(Original post by flux capacitor)
ok the carbon connected to the OH is a chiral centre? is that what i was missing?
Correct
1
reply
flux capacitor
Badges: 10
Rep:
?
#7
Report Thread starter 1 year ago
#7
(Original post by EdexcelAreIdiots)
Correct
Thanks, will look out for those in the future.
0
reply
flux capacitor
Badges: 10
Rep:
?
#8
Report Thread starter 1 year ago
#8
(Original post by EdexcelAreIdiots)
Correct
Your name is interesting. I had to switch from edexcel to OCR. I have not covered the whole syllabus of OCR yet but so far I have come across I think 2 things that seem to be easier on OCR. OCR don't bother with SN1/SN2. or half curly arrows. I wonder if they make up for it elsewhere?
0
reply
EdexcelAreIdiots
Badges: 9
Rep:
?
#9
Report 1 year ago
#9
(Original post by flux capacitor)
Your name is interesting. I had to switch from edexcel to OCR. I have not covered the whole syllabus of OCR yet but so far I have come across I think 2 things that seem to be easier on OCR. OCR don't bother with SN1/SN2. or half curly arrows. I wonder if they make up for it elsewhere?
I've had it since GCSEs lol. I actually do AQA, but from what my friends have told me OCR seems to be a bit harder than AQA.
0
reply
Kian Stevens
Badges: 16
Rep:
?
#10
Report 1 year ago
#10
(Original post by EdexcelAreIdiots)
I've had it since GCSEs lol. I actually do AQA, but from what my friends have told me OCR seems to be a bit harder than AQA.
OCR is easier than AQA in my opinion, not in terms of content (as I haven't seen what's different about both boards' specifications), but in terms of question wording. Their questions make a bit more sense to me. AQA seem to like asking 'strange' questions now and then...
0
reply
X

Quick Reply

Attached files
Write a reply...
Reply
new posts
Latest
My Feed

See more of what you like on
The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

Personalise

University open days

  • Bournemouth University
    Clearing Open Day Undergraduate
    Wed, 31 Jul '19
  • Staffordshire University
    Postgraduate open event - Stoke-on-Trent campus Postgraduate
    Wed, 7 Aug '19
  • University of Derby
    Foundation Open Event Further education
    Wed, 7 Aug '19

Are cats selfish

Yes (39)
50.65%
No (38)
49.35%

Watched Threads

View All