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Aqa chem 4/ chem 5 june 2016 thread

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Original post by Suits101
The carboxylic acid just accepts an H+, it doesn't loose an O - where would it go?

Google the question too, the products are NO3- and CH3COOH2+

It would go into water, the products you gave definitely work, but I think these do as well. Also where would that H attatch to the ethanoic acid?


NO3- H2O and CH3C+O makes sense for me, losing an OH with the H of HNO3
What did you guys put for the initial rate of reaction questions as to why its used?
Original post by elizabethsophie
Could I put Ni and hydrogen with high pressure instead of LiAlH4 for the reduction of the hydroxynitrile to the amine question?


yeah that's right
if i said to distinguish the acyl chloride i add nh3 would that still be right as white misty fumes still produced
Original post by cowie
Good point. Perhaps my correction was wrong..
I completely skipped over the fact that it had to be secondary or primary.. But I cannot see it being any other than a tertiary due to the number of peaks and the data given:/


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Same as me
Reply 1245
For the test for the acyl chloride, I put silver nitrate then white ppt. Do I get that or did the silver nitrate have to be acidified/aqueous or something?

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Original post by Ginpls
Are you sure no2 has a negative charge because in friedl crafts acylation, h2so4 also acts as a base: h2so4 + hno3 ---> no2+ +h2o + hso4-
And no2+ is formed


NO2 has a positive charge, NO3 is negative though
Mark Scheme pleaseee
Original post by SirRaza97
I put silver nitrate in aqueous solution. Forming white ppt for the halo alkane and nothing for the acyl one.


im pretty sure you can also say for the acyl chloride, using water/ammonia/alcohol/primary amine' would give you Misty fumes
and for the ketone/ haloalkane; no reaction
Original post by Fibsy
Damn, I wrote that it can be hydrolysed because it is polar, so it does not have to be removed, unlike the other polymer which is non-polar :/

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I think the answer will probably be that the polyester can biodegrade in the wound over time because it is hydrolysed. This means it doesn't have to be removed. Not sure if this is correct though...
Reply 1250
what did you get for the synthesis question? the five mark to do with compound s and step 3 and 4:frown:
image.jpg
Original post by Anno007
It's not correct because it doesn't have a triplet peak at 3.1-3.9

There must be a -COCH2CH2-
Original post by Fibsy
Damn, I wrote that it can be hydrolysed because it is polar, so it does not have to be removed, unlike the other polymer which is non-polar :/

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i wrote that too & i know a few who did. I don't see why it would be wrong
Original post by FormlessBowl
It would go into water, the products you gave definitely work, but I think these do as well. Also where would that H attatch to the ethanoic acid?


NO3- H2O and CH3C+O makes sense for me, losing an OH with the H of HNO3


That's why I doubted my answer, however I've linked the markscheme with the answer below this quote:

Original post by FormlessBowl
NO2 has a positive charge, NO3 is negative though


Markscheme for reaction with ethanoic acid and nitric acid from a different exam board - only difference is that this is with propanoic acid, page 8 part (d):
http://www.ocr.org.uk/Images/61528-mark-scheme-unit-f325-equilibria-energetics-and-elements-june.pdf
Reply 1254
Original post by Weeksy97
image.jpg


So sneaky... I assumed the -CH2CH2- had to be attached to the O-CH3 not the -OH damn -_-


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Original post by K2Cr2O7
I put H2O.
haloalkane - no change
Acyl chloride - misty fumes
???? not sure though


Using AgNO3 is the answer AQA were probably looking for
however i wrote the same as you and im 99% we are right
Original post by lishakb97
I'm glad that you did well but it definitely was a hard paper compared to previous years, many people found it hard so the boundaries will be low


It was a joke, one of my favorite sources of entertainment is boasting for getting 100% in really hard tests, although its funnier in real life...

In reality I did terribly in that paper, but chem5 is much easier than chem4 imo so ill have to make up for it. I got an A at AS and i think this paper was a high D low C, so with good chem 5 i might scrape aa low A or high B.
Original post by Weeksy97
I think the answer will probably be that the polyester can biodegrade in the wound over time because it is hydrolysed. This means it doesn't have to be removed. Not sure if this is correct though...


yea thats what I wrote, about the biodegradability
Original post by SubwayLover1
Did anyone else put you could heat and distill off the alcohol ??


yes!!
Original post by 1magicmo
13459642_1058564247553795_169885398_n.jpg
This is what I got :smile:


correct

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