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Aqa chem 4/ chem 5 june 2016 thread

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4.5k signatures nearly, such madness
Even if they do lower grade boundaries I still don't think I would've managed anything higher than a C, that exam was awful and my mind went totally blank and messed up on loads of questions, especially the synthesis questions, the 9 marker and the pH ones :frown:
anyone put reversible sign for the very first question?
Original post by ravichauhan11
anyone put reversible sign for the very first question?


I didn't for both first and second. They'll allow either way, as the question referred to a reaction between but it was technically reversible (as is every chemical reaction depending on the conditions).
Hey does anyone have a full list of colour changes that we need to know?

Even tho aqa will probably ask us why surgical stitches are blue and not green 🙄
Original post by Cadherin
I didn't for both first and second. They'll allow either way, as the question referred to a reaction between but it was technically reversible (as is every chemical reaction depending on the conditions).


yeah i only put a reversible sign for the first equation and not the second
does anyone have the paper?
Original post by Jonnyss
For the reaction with NaOH, could you use an acid catalyst as the conditions?


That's exactly right
Original post by Cave Felem
Did nobody else say fractional distillation? The alcohol has a different boiling point to the other compounds so it should be legit right?


I messed that question up.

However, I agree with your answer.
Original post by Suits101
I messed that question up.

However, I agree with your answer.


The boiling point isn't different enough for the alcohol to actually boil off at a different fraction without huge contamination - what they wanted is 'chromatography' I think.
Original post by Cadherin
The boiling point isn't different enough for the alcohol to actually boil off at a different fraction without huge contamination - what they wanted is 'chromatography' I think.


Damn I put that originally! :smile:
Original post by Cadherin
The boiling point isn't different enough for the alcohol to actually boil off at a different fraction without huge contamination - what they wanted is 'chromatography' I think.


They're normally both accepted on mark schemes. The industrial process of fermentation and spirit production relies on distillation of alcohol from water so it's definitely possible!
Original post by Cave Felem
They're normally both accepted on mark schemes. The industrial process of fermentation and spirit production relies on distillation of alcohol from water so it's definitely possible!


Exactly this.

I originally put chromatography to be on the safe side and then completely changed it.

I was stuck between (fractional) distillation, chromatography and reflux - why did I go mad and put reflux!?
Original post by Suits101
Exactly this.

I originally put chromatography to be on the safe side and then completely changed it.

I was stuck between (fractional) distillation, chromatography and reflux - why did I go mad and put reflux!?


I said heat the alcohol and distill off the product ? Is that correct?
Original post by SubwayLover1
I said heat the alcohol and distill off the product ? Is that correct?


What was the answer? Fractional distillation?

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Original post by SubwayLover1
I said heat the alcohol and distill off the product ? Is that correct?


I believe that's for an aldehyde?
Original post by Suits101
Exactly this.

I originally put chromatography to be on the safe side and then completely changed it.

I was stuck between (fractional) distillation, chromatography and reflux - why did I go mad and put reflux!?


I'm more interested as to why you thought refluc would seperate anything xD
Original post by Suits101
I believe that's for an aldehyde?


but you had a ketone and an ionic salt - so you can still distill off a ketone because of different boiling points :smile:
Original post by SirRaza97
I'm more interested as to why you thought refluc would seperate anything xD


I was hoping it'd separate the alcohol! :L

I've never been good at these practical technique apparatus thingies!
Original post by SubwayLover1
but you had a ketone and an ionic salt - so you can still distill off a ketone because of different boiling points :smile:


I can't remember it now! You might be right.

I thought you had a sodium ethanoate and alcohol?

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