OCR B F335 - Chemistry by Design - 13th June 2012

Scroll to see replies

same here, 4 and 3 and didn't quote shifts. Did you say no splitting? I said that, because there is only one central carbon atom (where C=O is attached) and that -OH group causes no splitting...

yh, I said the same except for the latter point, I just said no adjacent carbons with hydrogen for both bonds

Reply 981

avataraang

Original post by moodychopin

your ####ing me...

No it didn't but i drew it out... wrongly! :frown:

Reply 982

Birterillo

Original post by Toshiya

Do you think there'll be more than one answer? I think the question said 'suggest' so surely what I drew (attached) also works?

But it said in the question that water was lost so wouldn't the atoms removed have to be in the hydrogen oxygen ratio 2:1?

Reply 983

mortaz786

Original post by Cleoleo

oh ****, did it say draw it ???

no but i chode too :tongue:

Reply 984

Rainbow_2010

OMG! that was one of the hardest papers ever!! wht were they thinkin?? hopefully the f334 will b much easier... though iv lost all motivation now :frown:

Reply 985

sophieccaunt

Really really hated this exam. Can't believe OCR feels the need to depress all their students with an exam that we couldn't answer!

Reply 986

1lozza1

what did people put for the colour change of the indicator

Reply 987

InkyOne

Original post by Ilyas

same here, 4 and 3 and didn't quote shifts. Did you say no splitting? I said that, because there is only one central carbon atom (where C=O is attached) and that -OH group causes no splitting...

Yeah I said that too - and then ratios 4:2:1:1 and 3:2:1

Reply 988

icedragon

Original post by Ilyas

same here, 4 and 3 and didn't quote shifts. Did you say no splitting? I said that, because there is only one central carbon atom (where C=O is attached) and that -OH group causes no splitting...

It was no splitting for 1 of them, but the OH group with a CH2 next to it would cause some splitting.

Original post by InkyOne

Don't worry - it didn't say to draw it, there was just a lot of space underneath

Yeah, I just talked about how the substitution preserved the delocalised system and gave it stability instead of addition. And named bromoalkene and bromobenzene.

Original post by Alex J

Although thats true, its not really a direct benefit it has on the environment. I don't think the mark scheme will say that unfortunately.

Hmmm, we'll see, you're probably right.

(edited 11 years ago)

Reply 989

Cleoleo

Original post by 1lozza1

what did people put for the colour change of the indicator

orange to green ?

Reply 990

moodychopin

Original post by Rainbow_2010

OMG! that was one of the hardest papers ever!! wht were they thinkin?? hopefully the f334 will b much easier... though iv lost all motivation now :frown:

we are all just sitting on here thinking the same thing haha

Reply 991

avataraang

I think that this was an A* paper aimed at the A* students mainly. Bye bye A* :frown:

Reply 992

moodychopin

Original post by avataraang

No it didn't but i drew it out... wrongly! :frown:

thank god, they shouldnt penalise you for drawing anything though, if they didnt ask for it.

Reply 993

Venomilys

Original post by InkyOne

Don't worry - it didn't say to draw it, there was just a lot of space underneath

I drew both just in case... a benzene ring with no double bonds and 6 Br atoms around, and then I wrote the real equation (not kekule):

Benzene + Br2 -> Bromobenzene (?) + HBr

originally kekule would be electrophillic addition, but in reality it is electrohpillic substitutiom.

that is all I can remember for this one...

EDIT: oh, and benzene doesn't go under electrophillic addition becuase of the stable delocalized ring thingy.

Reply 994

1lozza1

Original post by Cleoleo

orange to green ?

i put yellow to blue green... will that be okay :s-smilie:

Reply 995

avataraang

Please please please OCR... if you have any compassion please lower the grade boundaries below 80.

Reply 996

InkyOne

Original post by Cleoleo

orange to green ?

Yup - same here

Reply 997

icedragon

Original post by 1lozza1

what did people put for the colour change of the indicator

For the aldehyde thing? Orange to green.

Reply 998

mortaz786

Original post by Cleoleo

for the nmr q, did people get one had 4 proton environments and one had 3 ? (there was just the one nmr question with infrared right?)
i didn't quote any chemical shifts :/

i think so, i also quoted shifts.. but did you say that it had no splitting as it wasnt attatached to any carbons whch had H's attatached?