# WJEC A-Level Chemistry A2 Unit 4 (18/06/2024)

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Original post by staycyoungluv
for the Rf value i got 4.32 so i drew the point on 5.32cm, but i'm so unsure about the last question bc i got (+) 44% and (-)56% but everyone else got sixty something or 75% for the negative enantiomer😭

the correct answer was around 64% for negative and 36% for posotive. As graph was a straight line from top left to bottom right.
Does anyone remember what they had for the solubility calculation and the one using d = m/v
Original post by Bobabbg
Does anyone remember what they had for the solubility calculation and the one using d = m/v

45cm^3 I think I got
Original post by el456
45cm^3 I think I got

for the d=m/v one
Original post by el456
45cm^3 I think I got

I had that for the first part, then I was kinda lost for the second so I did something - 7.15 and got 4 something?
Original post by Bobabbg
I had that for the first part, then I was kinda lost for the second so I did something - 7.15 and got 4 something?

was that the one at the bottom of the same page which had temperature in it? if so I couldn't do that one
Original post by el456
was that the one at the bottom of the same page which had temperature in it? if so I couldn't do that one

Yeah that one confused me. I think I had something different for the density one and I’m not too sure of my answer but I had 45cm^3 for the first part of the solubility one I think
Original post by el456
I think I said 2 environments because all the methyl carbon atoms were in one environment, and then all the other carbon atoms bonded to oxygen atoms were in another environment? idk if that's right

oh whoops I thought it was 3, because one for the methyl carbon atoms, one for the aromatic carbon atoms bonded to the oxygen atoms, and one for the aromatic carbons next to the methyl groups?? I was unsure tho😭🤷*♀️
Original post by Bobabbg
Yeah that one confused me. I think I had something different for the density one and I’m not too sure of my answer but I had 45cm^3 for the first part of the solubility one I think
The min volume was 45. And then the mass produced was 7.15g
Original post by Bobabbg
I had 7.15 in my answer but I thought it couldn’t be that simple because that was just half of 14.3 and the question was three marks so I was rly unsure of it

What did you get for the 6 marker
What did you get for the 6 marker

I had the empirical as C8H7BR3, but I messed up because I didn’t put a bromine on the benzene ring and it was meant to be because not all the moles of the compound reacted with silver nitrate
Original post by Bobabbg
I had the empirical as C8H7BR3, but I messed up because I didn’t put a bromine on the benzene ring and it was meant to be because not all the moles of the compound reacted with silver nitrate

Oh I did the same. Wait you still might 4 or 5 marks for highlighting observations.
Also there was a question at the beginning on colour of azo dyes and how its yellow I think. Did you talk about chromophore in your answer ?
Also there was a question at the beginning on colour of azo dyes and how its yellow I think. Did you talk about chromophore in your answer ?

Nooo I didn’t but I think I should have. I just said that the colour not absorbed is reflected and that the colour absorbed would be the opposite end of the colour wheel from yellow
Original post by Bobabbg
Nooo I didn’t but I think I should have. I just said that the colour not absorbed is reflected and that the colour absorbed would be the opposite end of the colour wheel from yellow

Oh ok what do you reckon will be the grade boundaries in this paper for an A .
Oh ok what do you reckon will be the grade boundaries in this paper for an A .

I honestly don’t know, do you think it’ll be like 2019?
Original post by Bobabbg
I honestly don’t know, do you think it’ll be like 2019?
I think so, i feel like overall it was a better paper than last year
Original post by chloe332
I think so, i feel like overall it was a better paper than last year

I’m so done
Original post by romanfurey
The min volume was 45. And then the mass produced was 7.15g

I used 7.15 in my calculation but i thought it couldnt be that straightforward because 7.15 was just 14.3/2, and the calculation was 3 marks.
Original post by Bobabbg
I used 7.15 in my calculation but i thought it couldnt be that straightforward because 7.15 was just 14.3/2, and the calculation was 3 marks.

Did you do the 1 HNMR question where it asked for the peaks on I think (ch3)3cCO. Did you get a triplet and a singlet?