Edexcel A2 Chemistry Exams -6CH04 (14th June) and 6CH05 (22nd June) Discussion Thread

Original post by ilovecake123

where was that link you put up for the grade boundaries ?

A screenshot from a quick spreadsheet I made earlier
Attached again

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1465936198227.jpg48.6KB

Reply 1321

ughexams

1

Original post by Don Pedro K.

Ahh okay haha so I lost that one then. What were the options for the one before that? I remember one of them being "attacks a planar site" or something which isn't right for the C-Br one but yeah

options were something along the lines of
both substitution
both addition
one forms racemic mixture
one undergoes elimination
so elimination is really the only one that fits given that it was symmetrical?

Original post by C0balt

I don't think it was eliminationAFAIK in elimination there should also be a double headed arrow from one of C-H bond to form C=C

it asked what is happening in that step, not the overall mechanism, and a Br- was eliminated in that step?

(edited 7 years ago)

Reply 1322

Original post by C0balt

A screenshot from a quick spreadsheet I made earlier
Attached again

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thanks

i could find it in previous pages! too many to sift through! grade boundary predicitons for an A? 66?

Reply 1323

Don Pedro K.

9

I'm honestly so scared for unit 5 lol

Reply 1324

Original post by ughexams

options were something along the lines ofboth substitutionboth additionone forms racemic mixtureone undergoes elimination so elimination is really the only one that fits given tat it was symmetrical?
it asked what is happening in that step, not the overall mechanism, and a Br- was eliminated in that step?

I thought it was an elementary step in the mechanism and elimination as a definition has to lose a small molecule and not just an ion afaik so I don't think it was right to lose bromide and say it was elimination
Though I'm now not very confident about its being racemic mixture either, I really want to see the paper now

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Reply 1325

Original post by ilovecake123

thanks

i could find it in previous pages! too many to sift through! grade boundary predicitons for an A? 66?

Yeah 66-68 I guess

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Reply 1326

Don Pedro K.

9

Original post by C0balt

I thought it was an elementary step in the mechanism and elimination as a definition has to lose a small molecule and not just an ion afaik so I don't think it was right to lose bromide and say it was elimination
Though I'm now not very confident about its being racemic mixture either, I really want to see the paper now

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random question but do you remember how many marks working out [HS-] was?

Reply 1327

Original post by Don Pedro K.

random question but do you remember how many marks working out [HS-] was?

2 I think

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Reply 1328

ughexams

1

Original post by C0balt

I thought it was an elementary step in the mechanism and elimination as a definition has to lose a small molecule and not just an ion afaik so I don't think it was right to lose bromide and say it was elimination
Though I'm now not very confident about its being racemic mixture either, I really want to see the paper now

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I definitely wouldn't have described it as an elimination if it wasn't multiple choice, but given that it was, elimination was the only option that was not definitely wrong (The halogenoalkane was definitely 2-bromopropane, I originally marked racemic but changed it in my check through)

Reply 1329

ughexams

1

Original post by Don Pedro K.

I'm honestly so scared for unit 5 lol

same so much same so so so much same

Reply 1330

Original post by ughexams

I definitely wouldn't have described it as an elimination if it wasn't multiple choice, but given that it was, elimination was the only option that was not definitely wrong (The halogenoalkane was definitely 2-bromopropane, I originally marked racemic but changed it in my check through)

Well then good bye to one mark lol

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Reply 1331

Original post by C0balt

Well then good bye to one mark lol

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wait why isn't it a racemic mixture?

Reply 1332

Original post by ilovecake123

wait why isn't it a racemic mixture?

According to that person the molecule was symmetrical?

Reply 1333

Original post by ilovecake123

wait why isn't it a racemic mixture?

Actually you know what even if the bromo was symmetrical it was not going to be racemic anyway, and if the carbonyl compound wasnt symmetrical (I don't think it was? Do you remember?) then it would form racemic

Reply 1334

Original post by C0balt

According to that person the molecule was symmetrical?

I'm pretty certain it weren't? it was ch3cohccn then something like c2h5

Reply 1335

Original post by C0balt

Actually you know what even if the bromo was symmetrical it was not going to be racemic anyway, and if the carbonyl compound wasnt symmetrical (I don't think it was? Do you remember?) then it would form racemic

exactly and the question specifically said property of one and not both?

Reply 1336

Original post by ilovecake123

I'm pretty certain it weren't? it was ch3cohccn then something like c2h5

Maybe then my dream for full UMS still lives 😅 meh it's over, gotta work on C3 for tomorrow lol

Reply 1337

Original post by ilovecake123

exactly and the question specifically said property of one and not both?

Yeah it was one

Reply 1338