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Edexcel A2 Chemistry Exams -6CH04 (14th June) and 6CH05 (22nd June) Discussion Thread

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Original post by C0balt
Assumption is that dH therefore dS system is unchanged


Yeah I just said delta S system remains constant
Original post by C0balt
I am convinced that i am illiterate but to me it made sense that they used the word slightly for decrease because the dS total was quite small anyway so a large decrease in temperature would've meant that the dS surroundings would be too negative and dS total would've become negative...so they didn't want us to talk about dS total becoming negative and so they said just slight decrease.... but I wouldn't be surprised if it was increase either because I have a history of ****ing up my exams with illiteracy


I think it was increase, and c0balt you don't ****ed up exams lol!
Original post by setarcos
It was 3 marks :\


What was the assumption? I said the slight decrease would lead to a less negative value for dS surroundings , which would mean larger total entropy , as its a sum of dSsystem and surroundings.
Just hoping for a low A/high B at least...surely that's not too much to ask for?
I put that if temperature increased Ssurr would be less negative and therefore Stot would be less negative and larger.

What did people put for the assumption?
Original post by Don Pedro K.
It was increase :/ I still interpreted it wrongly though and said delta S surroundings would become more negative even those it becomes less negative... Flipping hate this.

I doubt i'd get marks even though what I said was correct... they usually allow reverse argument for questions when asking generally about changing temperature but they specifically said increase :frown:
Original post by DesignPredator
I think it was increase, and c0balt you don't ****ed up exams lol!


Well f me lol I wanted 100% in A level chemistry :cry2:
Oh oh you don't know what happened in FP3 and M3 exams this year :lol:
Would saying that the assumption was that dSsystem remained constant/unchanged
Reply 1207
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nonok
1
Original post by C0balt
how many marks was that curve?
I think points to look out for are
- vertical sections at 25 and 50
- start at pH 1.5
- end at pH 12-13
- pH 1.9 (iirc) at 12.5cm3
- pH 7.2 (iirc) at 37.5cm3
- general shape
- marking equivalence points at middle of vertical sections



Why is there a vertical section at 25
Original post by nonok
Why is there a vertical section at 25


thats when first deprotonation ends
Original post by CLGC98
Would saying that the assumption was that dSsystem remained constant/unchanged


yes
Original post by C0balt
I doubt i'd get marks even though what I said was correct... they usually allow reverse argument for questions when asking generally about changing temperature but they specifically said increase :frown:


Well f me lol I wanted 100% in A level chemistry :cry2:
Oh oh you don't know what happened in FP3 and M3 exams this year :lol:


Wawa you're still getting in 😂, I screwed up FP2 quite badly so yep.
What did people get for the one where you had to use a2 maths?
For why salicylic acid was sparingly soluble what did you guys put?
For the differences between acid and base i put that with the base you can separate by adding by acid, but when you hydrolyse with acid you have to separate using distillation :redface:
I also put that ammonia is corrosive instead of saying toxic :frown:
Reply 1212
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_H_V
4
I was baffled by that, but then I saw on the calculator that if you press shift log it gives you the function of opposite log (10 to the minus x) and shift ln button gives 'e', so I just used that. Didn't know it was right but I had to something lol

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Original post by CLGC98
Would saying that the assumption was that dSsystem remained constant/unchanged


I said that too 😊

does anyone know how to find the value of Ka1 for that diprotic titration curve?
i redid one of my graphs on extra paper but forgot to write the question number...although i did write next to the actual graph on the exam paper that it was redrawn on the extra sheet, do you think they'll mark it?
Original post by Beautywithabrain
What did people get for the one where you had to use a2 maths?


Something around 5x10^-3
I cant see why they wouldnt discount that question on the RlnK calculation
Original post by C0balt
Wasn't it slight decrease?


I messed up the titration curve too omg! :frown: 5 marks. I really want an A* as well. And for the entropy one, I said Ssurr will be a slightly less positive value since temperature has slightly increased. I said Ssys will remain the same and so Stotal will decrease by a small amount. ? I can't even remember
Original post by sayshay
I said that too 😊

does anyone know how to find the value of Ka1 for that diprotic titration curve?


half equivalence?
Exam was disgusting, unfair lnk question, i dont do maths a lvl how am i meant to know??? this exam ruined my chances of getting a place in uni. It was way worse than ANY past papers i've done!!!!!!!!!!! Boundaries should be like 55/90 A FFS

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