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

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Reply 20

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.

Reply 21

Bobabbg

Does anyone remember what they had for the solubility calculation and the one using d = m/v

Reply 22

el456

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

Reply 23

el456

Original post by el456

45cm^3 I think I got

for the d=m/v one

Reply 24

Bobabbg

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?

Reply 25

el456

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

Reply 26

Bobabbg

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

Reply 27

bluemuffin986

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😭🤷*♀️

Reply 28

romanfurey

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

Reply 29

Jroy

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

Reply 30

Bobabbg

Original post by Jroy

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

Reply 31

Jroy

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.

Reply 32

Jroy

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 ?

Reply 33

Bobabbg

Original post by Jroy

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

Reply 34

Jroy

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