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Aqa chem 4/ chem 5 june 2016 thread

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Original post by ravichauhan11
Yeah that's the normal way, would my way still get the marks?


It sounds as if there were alternatives - the mark scheme should be quite lenient. As long as you genuinely show the given result, you should get full marks.
Original post by Alevels16
I thought filtration was okay?


Filtration, but you'd need an inert solvent.
I thought chromatography was the standard answer they wanted?
Original post by Ljm1998
All your teachers will have the paper, just go to them and ask to see it and take photos or whatever,
Now I hope everyone's in "AQA CHEM4 2016 Complaints" on Facebook? We've got replies from the daily mail so join and we will grow and sign the petition more and get fairer results


I don't think it was unfair. Yes it was tricky and a bit weird, but fair, and grade boundaries will be adjusted accordingly (i.e. my teacher thinks it will be 88 maximum for 120 UMS)

All the people moaning about it relied too much on past papers and not enough on understanding of the subject. Petitions and protesting will do nothing - just focus on smashing CHEM5!
Since the separation one was on about separating getting the carboxylic acid from the carboxylic acid, wouldn't you just add HCl or something then filter out the salt? Thinking chromatography won't produce an acid from an ion
Original post by Aethrell
Since the separation one was on about separating getting the carboxylic acid from the carboxylic acid, wouldn't you just add HCl or something then filter out the salt? Thinking chromatography won't produce an acid from an ion


I don't think it was separating two carboxylic acids - I think one was an alcohol and the other had carbonyl (it may have been carboxylic acid). Since the alcohol is more polar, it would be attracted to the stationary phase and the carbonyl compound to the eluent.
Original post by Cadherin
I don't think it was separating two carboxylic acids - I think one was an alcohol and the other had carbonyl (it may have been carboxylic acid). Since the alcohol is more polar, it would be attracted to the stationary phase and the carbonyl compound to the eluent.


It was in the same 3 marker as the base hydrolysis right?

If it was then that was talking about an ester being hydrolysed to a carboxylate salt and an alcohol. If I remember correctly, the question asked how it could get the acid.

Could be very wrong though...
Original post by ravichauhan11
Yeah that's the normal way, would my way still get the marks?


I don't see why not! :smile:

Original post by Aethrell
Since the separation one was on about separating getting the carboxylic acid from the carboxylic acid, wouldn't you just add HCl or something then filter out the salt? Thinking chromatography won't produce an acid from an ion


Adding HCl would turn the salt into a carboxylic acid and NaCl - it would then still be mixed with the alcohol.
Original post by Suits101
I don't see why not! :smile:



Adding HCl would turn the salt into a carboxylic acid and NaCl - it would then still be mixed with the alcohol.


Ah ****, yeah. I see now.

I thought it meant getting an acid from the salt.

Completely disregarded the alcohol >.>
Original post by Aethrell
Ah ****, yeah. I see now.

I thought it meant getting an acid from the salt.

Completely disregarded the alcohol >.>


I said heat under reflux so I'm in no position to judge!
When I did the molecular formula question, I divided the 1.5...whatever it was by 2 and then divided all the numbers by that number to get the ratio for the molecular formula rather than obtaining the empirical formula and multiplying by 2. Full marks or would I end up losing a mark for this?
Reply 1690
Avatar for ELCRE
ELCRE
5
The petition has made me feel much better but my chemistry grade is in serious jeopardy. I'm so worried i don't even think lowering thr grade boundaries will help me much. I'm scared I will get a U & it's even more frustrating because I panicked so much & ran out of time for questions which I would've otherwise been able to do :frown:


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Original post by Suits101
I don't see why not! :smile:



Adding HCl would turn the salt into a carboxylic acid and NaCl - it would then still be mixed with the alcohol.


Did nobody else say fractional distillation? The alcohol has a different boiling point to the other compounds so it should be legit right?
Original post by Suits101
I said heat under reflux so I'm in no position to judge!


For the reaction with NaOH, could you use an acid catalyst as the conditions?
Original post by ELCRE
The petition has made me feel much better but my chemistry grade is in serious jeopardy. I'm so worried i don't even think lowering thr grade boundaries will help me much. I'm scared I will get a U & it's even more frustrating because I panicked so much & ran out of time for questions which I would've otherwise been able to do :frown:


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Tbh, if they made a new paper in the old style with actual questions from the spec, I would be more than willing to do it!
https://www.change.org/p/aqa-lower-grade-boundaries-for-mpc3

Please sign
Reply 1695
Avatar for ELCRE
ELCRE
5
Original post by cookiemonster15
Tbh, if they made a new paper in the old style with actual questions from the spec, I would be more than willing to do it!


Yes me too, I was stressing so much that I had a dream thry actually let me do it but woke up to this shite reality


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Original post by ELCRE
Yes me too, I was stressing so much that I had a dream thry actually let me do it but woke up to this shite reality


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It's like aqa like screwing with our futures.....I needed a freaking A! -____-
There's a petition to lower the grade boundaries on the AQA Chemistry 4 paper on "ipetitions". It's aiming to gather 15,000 signatures and can be found by either googling "lower grade boundaries for CHEMISTRY UNIT 4 2016" or going to the Facebook page "aqa chem4 complaints". It's at 4000+ currently and by getting friends and family to sign hopefully aqa will have to review. :smile:
Original post by Ninaleah1234
There's a petition to lower the grade boundaries on the AQA Chemistry 4 paper on "ipetitions". It's aiming to gather 15,000 signatures and can be found by either googling "lower grade boundaries for CHEMISTRY UNIT 4 2016" or going to the Facebook page "aqa chem4 complaints". It's at 4000+ currently and by getting friends and family to sign hopefully aqa will have to review. :smile:


Here's the link to the Ipetitions


http://www.ipetitions.com/petition/lower-grade-boundaries-for-chemistry-unit-4-2016
Original post by ELCRE
The petition has made me feel much better but my chemistry grade is in serious jeopardy. I'm so worried i don't even think lowering thr grade boundaries will help me much. I'm scared I will get a U & it's even more frustrating because I panicked so much & ran out of time for questions which I would've otherwise been able to do :frown:

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Yep same here, I'm resitting this exam so I was aiming to get a low A at best but now I'm most likely going to end up with a D again for CHEM4 and not get into uni - Thanks AQA :smile:

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