[Who_Is_It?]

(Original post by lopikase123)
its so nice to be finished like, what did you draw for the benzene delocalisation one?? before and after?? i think the azo thing was 4 hydroxy azo benzene or something like that

I drew the kekule structure with alternating double and single bonds for the first one then the normal benzene with the circle for the second one I think it's right...

I've never heard of that compound in my life!! Gutted I didnt get it... Only one mark though, I wrote coloured for the appearance

What did everyone get for the appearance for the nitro benzoate methyl thingy??

[lopikase123]

i said yellow oily liquid but who knows like, what is a kekule structure??

[Who_Is_It?]

(Original post by lopikase123)
i said yellow oily liquid but who knows like, what is a kekule structure??

I said a white solid

It's the structure of benzene with no delocalised pi electrons, it forms double and single bonds instead between the carbons. What was the name of the monomer on the very last question??? I got 3-methylprop-2-ene

[d3ano]

I thought it was good enough as a paper. Although which has less basic character phenylamine or ethanamide? Also, I wasn't sure which poisiton the NO2 would go on so I said position 3 when it asked and put a side not saying that there were isomers and named them. Would that be okay?

For the benzenes I first drew kekulé's structure which was hexan-1,3,5-triene and then our normal benzene, but because it said to show the p-orbitals I gave the shape of how they would overlap and drew the p orbitals in instead of drawing just a ring. Would this be acceptable?

Thanks guys!

[d3ano]

(Original post by Who_Is_It?)
I said a white solid

It's the structure of benzene with no delocalised pi electrons, it forms double and single bonds instead between the carbons. What was the name of the monomer on the very last question??? I got 3-methylprop-2-ene

It is, it's a white crystalline solid

[Who_Is_It?]

(Original post by d3ano)
It is, it's a white crystalline solid

Ohhh yeaaa, I feel like a lord for guessing that

I'm not completely sure about your NO2 question but if you put both the p orbitals and the benzene structures I'm sure that would be fine They can't penalise you for giving extra information.

Also I think ethanamide has more basic character?? Although I'm probably wrong, cause the lone pair could be drawn into the delocalised ring in phenylamine reducing its availability even more so than in ethanamide :s

[ms607]

(Original post by Who_Is_It?)
Ohhh yeaaa, I feel like a lord for guessing that

I'm not completely sure about your NO2 question but if you put both the p orbitals and the benzene structures I'm sure that would be fine They can't penalise you for giving extra information.

Also I think ethanamide has more basic character?? Although I'm probably wrong, cause the lone pair could be drawn into the delocalised ring in phenylamine reducing its availability even more so than in ethanamide :s

arent amides neutral?

[d3ano]

I agree that the order was phenylamine first because it's delocalisation was most stable, and more stable than that given by the pi electron in an amide, so although both have negligable basic character, it was greater in ethanamide.

[Who_Is_It?]

(Original post by ms607)
arent amides neutral?

Ohhh yea your right sorry... I was thinking of something completely different

Yea they're neutral, so phenylamine will have more basic character. Slightly embarrassing after just doing a test on this stuff

[d3ano]

They're only neutral because of the delocalisation, which there is more of in phenylamine though.

[ms607]

(Original post by d3ano)
They're only neutral because of the delocalisation, which there is more of in phenylamine though.

yes but amides are neutral whilst phenylamine still has weak basic character

also I just looked up some pKb values and they agree that methylamine > phenylamine > ethanamide in basicity

[d3ano]

Okay, pKb values are accepted :P
Do you guys think the marks will be scaled up much, because in A21 I got 102 and it scaled up to 111. Do you think it'll be similar?

[ms607]

(Original post by d3ano)
Okay, pKb values are accepted :P
Do you guys think the marks will be scaled up much, because in A21 I got 102 and it scaled up to 111. Do you think it'll be similar?

ooh, lucky you :O I never found out my raw mark but it mustn't have been that great because I got 98 in january

as for this paper, I can see it being scaled up, as there were some questions that were unusual and probably caught a lot of people out, though I couldn't make a good enough guess as to how much it would...

[Who_Is_It?]

(Original post by ms607)
ooh, lucky you :O I never found out my raw mark but it mustn't have been that great because I got 98 in january

as for this paper, I can see it being scaled up, as there were some questions that were unusual and probably caught a lot of people out, though I couldn't make a good enough guess as to how much it would...

Yea, I can see why it might be scaled up, there were a few questions that would have tripped quite a few people up. Fingers crossed the scaling is nice for this one

How many marks do you reckon I would have lost for drawing the mechanism with methyl benzene instead of methyl benzoate?? Cause that means i got the name of the thing wrong after... damn!!

[callumbm]

(Original post by ms607)
yes but amides are neutral whilst phenylamine still has weak basic character

also I just looked up some pKb values and they agree that methylamine > phenylamine > ethanamide in basicity

I concur. Amides are actually slightly acidic in nature. Phenylamine is only slightly basic because the benzene ring draws in the electrons from N. Whilst amines are the most basic as the alkyl groups push electrons onto N, increasing its electron density.

[ms607]

(Original post by Who_Is_It?)
Yea, I can see why it might be scaled up, there were a few questions that would have tripped quite a few people up. Fingers crossed the scaling is nice for this one

How many marks do you reckon I would have lost for drawing the mechanism with methyl benzene instead of methyl benzoate?? Cause that means i got the name of the thing wrong after... damn!!

hmm... no idea... maybe 1 or 2 marks because it's showing a correct electrophilic substitution mechanism with NO2(+)

I drew methyl benzoate correctly but drew the nitronium ion joining onto position 2 of the benzene ring instead of 3 (I assume it was 3 because then the product would have been methyl 3-nitrobenzoate?) meaning my product name was wrong

[Who_Is_It?]

(Original post by ms607)
hmm... no idea... maybe 1 or 2 marks because it's showing a correct electrophilic substitution mechanism with NO2(+)

I drew methyl benzoate correctly but drew the nitronium ion joining onto position 2 of the benzene ring instead of 3 (I assume it was 3 because then the product would have been methyl 3-nitrobenzoate?) meaning my product name was wrong

Thank god, its not all lost then You'll probably get follow through marks for the name though.

Another question:
See for the half equation for VO2+ to V2+ did you include water, hydrogen ions and electrons?
And the emf calculation for the zinc and aluminium did you have to multiply the each emf value by 2 or 3 based on your equation??

[ms607]

(Original post by Who_Is_It?)
Thank god, its not all lost then You'll probably get follow through marks for the name though.

Another question:
See for the half equation for VO2+ to V2+ did you include water, hydrogen ions and electrons?
And the emf calculation for the zinc and aluminium did you have to multiply the each emf value by 2 or 3 based on your equation??

for the emf values, you never change the numbers, only the signs if you use the reverse reaction, regardless of whether a reaction needs to be multiplied to balance charges, so no

for VO₂⁺ to V²⁺ I just balanced it as I normally would, so it would have been VO₂⁺ + 4H⁺ + 3e^- > V²⁺ + 2H₂O ???? (assuming it was VO₂⁺ and not VO²⁺, can't really remember)

[Who_Is_It?]

(Original post by ms607)
for the emf values, you never change the numbers, only the signs if you use the reverse reaction, regardless of whether a reaction needs to be multiplied to balance charges, so no

for VO₂⁺ to V²⁺ I just balanced it as I normally would, so it would have been VO₂⁺ + 4H⁺ + 3e^- > V²⁺ + 2H₂O ???? (assuming it was VO₂⁺ and not VO²⁺, can't really remember)

Awww damn... see this is why I stick to maths and physics, there's none of this business with half equations or balancing equations!!! But I did manage to balance the vanadium equation right

Thank you

[GarySpurs]

(Original post by ms607)
we had it in our notes as 4-hydroxyazobenzene

Our teacher told us that it was 4 hydroxyphenylazobenzene as there was 2 benzenes that had to be addressed.

About the Multiple choice questions, Im sure Amides are neutral, if not basic at all, phenylamine is a weak base and amine is highly basic so it should have been for increasing basic strength:

Amide - Phenyamine - Amine

Am I right?

Also stuck down white crystalline solid for the appearance of methyl 3-nitobenzoate.

Over all I thought it was meh, hated the nmr question, was thanking the gods for the dichromate question. Overall Im unsure of how I done. This test reminded me so much of the a2 1 summer 2011 paper which also had so much drawing in it.

Goodluck you guys.