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Equilibria, Energetics and Elements (F325) - June 2011 Exam.

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Rofl. I think this paper was just as hard as the Jan paper, though I think I've done 'okay' this time. Couldn't do the last question, but apart from that, the rest was decent I think.
Think I will get around 65 raw marks. Which hopefully will be an A.
Original post by SaturnineDragonfly
I was thinking about (trying to remember :tongue:) what was in that box, since it had some information about ratios. I'm glad I chose lactic acid, although it was for the wrong reason, but it will only be 1 mark for the reason I expect. :confused: How did you respond to the validity part of that question?


It said 'deduce the chemicals' not 'ecplain why you chose these chemicals' so as long as you got the right answer you should be ok :smile:

Ka varies with temperature, so I said of the sweets are not eaten at 25 degrees the pH will be different. In that case the magic tang thing will be invalid.
Reply 2022
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786girl
for the last question i just worked out the moles of that thingg and divided it by 2 (total guess) then got a percentage of like 13%... haha
omg i cant believe i am laughing my future depended on thiss exam it was horrible!!!!!!!!!!!!!!!!!!
i almost burst out crying in the exam i dont know what to do or say im so so so so guttted :frown:

what did u guys get for the complex ions?

when it was substitued by hcl was it ni(cl)4?
Original post by student777
Pg 153, blue box :smile:



Original post by percy93
don't worry i don't think it matters what acid you chose, they're looking for the calc at the end of the day :smile:


****... :'(
Also were you able to work out the concentrations or just the ratios? like conc of salt = 0.23 x conc of acid because thats all I got up to...
Original post by VetApplicant2011
Did this exam completely ass rape anyone else? I couldnt do any of the massive questions.. the Gibbs free energy one OR the buffers one OR the last one..

And did anyone get a massive value of Hydration of Cl- for like the first question?


I went into the exam super confident thinking i was going to rape it but damn i can't even sit down now cus it hurts so much.

Hydration of Cl- i got some massive figure. Was 2000 and something cant remember now.
Reply 2025
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susan23
3
Original post by Student21
I did not say i found it easy. I revised 4 times for this paper and still failed.


ohh sorry that wasn't directed at you personally!

yh same :frown:
Original post by VetApplicant2011
Did this exam completely ass rape anyone else? I couldnt do any of the massive questions.. the Gibbs free energy one OR the buffers one OR the last one..

And did anyone get a massive value of Hydration of Cl- for like the first question?


Yeah I got a massive negative value for this. Did the whole hydration = lattice enthalpy + solution.
Original post by student777
It said 'deduce the chemicals' not 'ecplain why you chose these chemicals' so as long as you got the right answer you should be ok :smile:

Ka varies with temperature, so I said of the sweets are not eaten at 25 degrees the pH will be different. In that case the magic tang thing will be invalid.


....omg your right about the temperature thing :/ its so clear now, why couldn't I get that in the actual exam!
Reply 2028
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J DOT A
Original post by Heatheroink123
For delta G,

I got delta S to be -0.285

1000 x -0.285 = -285

176--285 = 461


I may have got the numbers slightly wrong as I can't remember them for definite but it was roughly this. I believe.


Your telling me that 176-285=461?
Reply 2029
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Oink123
7
Did anyone get uses for H2 as hydrogen fuel cell vehicles and margarine production? Or does anyone know if they're right?
Original post by susan23
who found that easy??? Im sorry but how??? What kind of revision did you ****ing do??? Because i seem to be missing somehting here...every ****ing person in my college found it ok...ok.??!?! Ok?!?!? I cudnt even attempt the ****ing questoins forget even trying to find it ok?!?!?


this is EXACTLY how I feel. Everyone came out going.. well that was a pretty good paper wasnt it?

I literally didnt even know how to start half of the questions. What the actual ****?
Reply 2031
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Rob16
Original post by ruby321
....omg your right about the temperature thing :/ its so clear now, why couldn't I get that in the actual exam!


Agreed :frown:
Reply 2032
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susan23
3
Original post by MasterJomi
Rofl. I think this paper was just as hard as the Jan paper, though I think I've done 'okay' this time. Couldn't do the last question, but apart from that, the rest was decent I think.
Think I will get around 65 raw marks. Which hopefully will be an A.


LOOOOOOOOOOOOOOOOOOooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooOOOOOOOOOOOOOOOOOooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooL
Reply 2033
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pan_93
Original post by percy93
i got C10H12N2


I ****ED this exam up so bad...not only was it so ****ing hard but the ones u i should have got right i made pathetic errors on...

I got C10 H8 N2
Reply 2034
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Rocks:)
2
Original post by VetApplicant2011
Did this exam completely ass rape anyone else? I couldnt do any of the massive questions.. the Gibbs free energy one OR the buffers one OR the last one..

And did anyone get a massive value of Hydration of Cl- for like the first question?


My Hydation of Cl was like -1000 or something. I hated all of this paper :frown:
I just cried after an exam for the first time in my life. I needed 93 UMS for an A and I may not make that. I got something ridiculous like 2880 for Kc and my percentage of copper was more than 100% after spending 20 minutes doing the ionic equations I had no time to check.
Original post by GiraffePoacher
I actually thought you could have picked any of them? Because I think the pH of the buffer depends more on the acid : salt proportions rather than the pH of the acid alone.

So for the sake of ease, I picked acetic (ethanoic) acid.

But I could be wrong.


yes...i agree with this


you can use any of the buffers, however the proportion of acid:salt will be different for each buffer in order to maintain a pH of 3.5
anyone amazing and beautiful offering to do unofficial mark shceme??
major rep for life!
Reply 2038
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percy93
why were the results not valid?
Original post by student777
It said 'deduce the chemicals' not 'ecplain why you chose these chemicals' so as long as you got the right answer you should be ok :smile:

Ka varies with temperature, so I said of the sweets are not eaten at 25 degrees the pH will be different. In that case the magic tang thing will be invalid.



I remember it said deduce, but when they ask that it feels better to put a reason at least. :s-smilie:

For validity, I wrote that if they taste-tested sweets with a pH of 3.55 and then taste-tested other sweets with different pH's but other conditions/ingredients in the sweet the same, then they could validly predict that it was the pH of 3.55/the acidity giving the magic tang.

It seems like that kind of question (about validity) could be quite open to many answers?

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