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OCR Chemistry A Exam Thread (Breadth - May 27 2016 and Depth - June 10 2016)

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it was butanoic aCid
you had TO times the EF C2H4O by two to get C4H802 OF WHICH THE MR WAS 88
THERE WAS ALSO AN M/Z PEAK AT 88 SUGGESTING IT WAS BUTANOIC ACID
IT COULDNT HAVE BEEN C2H40 SIMPLY BECUASE THAT ISNT A CARBOXYLIC ACID
THE IR SPEC CLEARLY INDICATED IT WAS A C ACID
THE MAS SPEC ALSO SAID THE MOST INTENSE PEAK WAS CAUSED BY A CARBOCATION WHICH WAS AT 43 OR 44
SO THE MR WAS 88
anyone agree?

I think for sure it was an isomer of butanoic acid, but I thought the only way for it to make a secondary carbocation was for it to have a methyl group, so methylpropanoic acid?

Reply 981

4nonymous

Original post by so_321

Wasn't it 67.5

It was 67.43... which rounds to 67.4%

Reply 982

so_321

Original post by 11234

67 percent alright to 2sf yea? Maybe?

What did you get?

Reply 983

asinghj

Original post by 4nonymous

Yh it would. Also I think for yield it was 67.4%
As for the last question 43 peak does work with butanoic acid because its (CH3CH2CH2)+ ? Although I aint sure

I think I might have gotten 67.4% just can't remember I know I had sixty something . 4 or 5

Reply 984

Tyler213

Original post by 4nonymous

It was 67.43... which rounds to 67.4%

it was 67.45 which rounds to 67.5%

Reply 985

11234

Original post by 4nonymous

It was 67.43... which rounds to 67.4%

Is 67 alright

Reply 986

HaveFa1th

No + o3 --> no2 o2
no2 + o --> no + o2

Reply 987

amysed

thank god other people also put 2-methylpropanoic acid😅😅 what do you guys think grade boundaries will be like then? still 80% for an A as it was quite an easy paper ?

Reply 988

4nonymous

Original post by 11234

Is 67 alright

Probably

Reply 989

TH3-FL45H

For the last question I put butanoic acid instead of 2 methyl propanoic acid :facepalm:

Figured it out 30 seconds after the exam finished ffs

How many marks will I lose? 2? 3?

Posted from TSR Mobile

Reply 990

4nonymous

Original post by Tyler213

it was 67.45 which rounds to 67.5%

No it was 67.43. Did you use exact values or rounded values because I used exact.

Reply 991

asinghj

Original post by awsomedude

what did people write for the ozone depletion propagation steps?

no• + o3 -> no2• + o2
no2• + o -> no• + o2

(edited 7 years ago)

Reply 992

so_321

Original post by Tyler213

it was 67.45 which rounds to 67.5%

Yeah I think that's what it was

Reply 993

11234

Did anyone get near 5.7x10-4 for rate

Reply 994

asinghj

Original post by 4nonymous

No it was 67.43. Did you use exact values or rounded values because I used exact.

They will probably allow 67.4 to 67.5

Reply 995

11234

Original post by asinghj

bo• + o3 -> no2• + o2
no2• + o -> no• + o2

Would we lose marks dor puting the dot on the wrong element I put it next to nitrogen

Reply 996

alevelnerd123

Original post by TH3-FL45H

For the last question I put butanoic acid instead of 2 methyl propanoic acid :facepalm:

Figured it out 30 seconds after the exam finished ffs

How many marks will I lose? 2? 3?

Posted from TSR Mobile

1, if that. If a lot of people but butanoic acid they might accept it... because it's not wrong as such, it's just a different isomer. I did the same as you