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Edexcel IAL, Unit 4: Rates, Equilibria and Further Organic Chemistry. 14-Jun-2016

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Original post by Geethan
Rhombic Sulphur entropy question? Although the equation said "S (Rhombic) + 3F2......", the data booklet suggests that Sulpher Rhombic generally consists as 8 Sulphur atoms. So do we multiply the molar entropy of S rhombic by 8?


I think you are supposed to. It makes sense that way. I didn't do it. :frown:
Original post by Geethan
Rhombic Sulphur entropy question? Although the equation said "S (Rhombic) + 3F2......", the data booklet suggests that Sulpher Rhombic generally consists as 8 Sulphur atoms. So do we multiply the molar entropy of S rhombic by 8?


Where it was written that it consists of 8 Sulphur atoms ? And the data booklet says that the entropy in the table given applies to single atoms
Original post by PlayerBB
Where it was written that it consists of 8 Sulphur atoms ? And the data booklet says that the entropy in the table given applies to single atoms

Just one S atom in the equation, so I think muliplication is not required
Original post by 12103763d
Just one S atom in the equation, so I think muliplication is not required


Yeah I believe that as well, but he's referring that in the data booklet it says that this Sulphur atom consists of 8 sulphur atoms or something!
Reply 144
volume vs rate
Original post by Maria247
That was a rate concentration graph.
Reply 145
You did not do it? why??
Original post by Sandy_Vega30
I think you are supposed to. It makes sense that way. I didn't do it. :frown:
Reply 146
It would be a curve if it is 1st order in rate vs volume. and the half life is not constant, so it is not 1st order.
Original post by Sandy_Vega30
But 1000/ t is directly proportional to initial rate of reaction while volume of IO3- is directly proportional to concentration. SO technically it's like a graph of rate against concentration. Hence, it's first order. My teacher confirmed it after seeing the paper. :smile:
I didn't multiply by 8, i didn't notice it.
Original post by Quiton
volume vs rate


It is not volume Vs rate, It was 1000/t (Rate) against volume. So it is first order. I showed the question to my teacher after the paper. He said it is first order. :smile:
Reply 149
It would be a curve if it is first order. I meant the same thing by saying volume vs rate. And your teacher is not supposed to read your question papers after the exam ??

Original post by Sandy_Vega30
It is not volume Vs rate, It was 1000/t (Rate) against volume. So it is first order. I showed the question to my teacher after the paper. He said it is first order. :smile:
Reply 150
Oh don't worry.. you don't have to multiply by 8..
Original post by Sandy_Vega30
I didn't multiply by 8, i didn't notice it.
Original post by PlayerBB
Yeah I believe that as well, but he's referring that in the data booklet it says that this Sulphur atom consists of 8 sulphur atoms or something!

8 is the number of atoms per S molecule, if S exists as 8 atoms in equation, it multiplies by 8 to get that entropy, while if it exists as 1 atom, no multiplication is needed.
Take hydrogen as example, booklet says it has 2 atoms per molecule, so it normally exists as H2 in equation, multiplication of 2 is needed. If it exists as (1/2)H2, mathematically it contains only one H atom, so no multiplication is needed.
We can treat this S as (1/8)S8 alternatively, so for this, multiplication of 8 but also division of 8 is needed since it exists as 1 S atom, turning out no overall arithmetic. It's my opinion.
(edited 7 years ago)
Original post by Quiton
It would be a curve if it is first order. I meant the same thing by saying volume vs rate. And your teacher is not supposed to read your question papers after the exam ??


how did your graph look like? My teacher is allowed to see the extra papers that come along after the exam is over. Our papers are already sealed when he read it. So no prblem.
Original post by Blazyy
I'm pretty sure.
Can anyone confirm, just in case?


I wrote pipette as well :smile:
Original post by Blazyy
It was 5 marks, I think you'll get 2 or 3. What about the nmr spectra of propanoic acid? It had 3 peaks right, 2 triplets and 1 quartet


I got a singlet, quartet and a triplet :/
Original post by Sandy_Vega30
I think you are supposed to. It makes sense that way. I didn't do it. :frown:


Neither did I :frown:
Original post by Sandy_Vega30
I think you are supposed to. It makes sense that way. I didn't do it. :frown:


What was the skeletal formula of the ester formed? the one where something reacted with excess propanoic acid? :O
I am not sure. :frown:
Original post by notsoclueless
What was the skeletal formula of the ester formed? the one where something reacted with excess propanoic acid? :O


未命名.png this is my answer, not sure if it's correct or not
as it's excess propanoic acid (both carbonyl group react with propanoic acid)

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