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

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soo... the melting of water into ice, was that +, + ?
Ice into water sorry
(edited 12 years ago)
Original post by kingam
is there a raw mark ums converter


No, but to get an underestimate just x 1.5
so that if its low you can think that itll be higher as there will be low grade boundaries :smile:
Reply 2902
Avatar for kingam
kingam
Original post by Limesasquatch
No, but to get an underestimate just x 1.5
so that if its low you can think that itll be higher as there will be low grade boundaries :smile:


what ums have you got in all your exams so far lol
Reply 2903
Avatar for Dim0nIX
Dim0nIX
Original post by Thuzz
yeah i got second order
but i messed the rest of the question up :frown:
oh well a couple marks for stating the half life and saying it was second order hopefully


So it was second order?
Original post by Dim0nIX
So it was second order?


Some people are saying second order because of inconsistent half lives while the others are saying first order because of experimental difference or something like that.

I also put second order. We'll just have to wait for what OCR says.
Reply 2905
Avatar for BAPURAMT
BAPURAMT
there was a link to the paper but its not working anymore does any body else have the copy of the paper that you can send me the link to. thank you.
Original post by Student21
Some people are saying second order because of inconsistent half lives while the others are saying first order because of experimental difference or something like that.

I also put second order. We'll just have to wait for what OCR says.


I said it was first. It's such a stupid question because it even says in the textbook that we often don't use those graphs because it can be difficult to tell between first and second orders.

:angry:
Enthalpy/entropy was surely + + for ice/water question??
Original post by imperial maniac
I said it was first. It's such a stupid question because it even says in the textbook that we often don't use those graphs because it can be difficult to tell between first and second orders.

:angry:


it was quite clearly 1st order as half life was more or less constant. if you look at the graph it took 190s to half first time, but if you look where the crosses are the one nearest is actually slightly more to the right, so it probably is 200s, then it was 400s, and then at just after 600s

if it was 2nd order, it wouldn't have anywhere near a constant half life really.
Original post by wilsea05
it was quite clearly 1st order as half life was more or less constant. if you look at the graph it took 190s to half first time, but if you look where the crosses are the one nearest is actually slightly more to the right, so it probably is 200s, then it was 400s, and then at just after 600s

if it was 2nd order, it wouldn't have anywhere near a constant half life really.


Well thank the flying spaghetti monster for that.
Reply 2910
Avatar for samzurai
samzurai
it was first half according to my teacher because remember your interpreting a curve so more or less there abouts, if there was no values everyone would agree the curve is 1st order
Original post by susan23

Original post by susan23
ok heres the paper....http://s45.photobucket.com/albums/f94/touran22/f325/

password touran22

---------------------------------------------------------------------------------------------------------

could someone please tell me how many marks questions:

page 7 of the question paper
page 10 of the veiwing
page 14 of the question paper
page 16 of the question paper


omg when i looked into the paper again it is so much easier=.= .. anyways i have chosen benenecarboxylic acid does anyone think i will get a method mark for it?because i have worked out and the only thing being wrong is that chosen acid is not lactic acid or ethanoic acid.
=.=
i have commented on the temperature in the tounge is different from 25degree C and that these pH which these works might be different hence not able to produce the sweet tang .
(edited 12 years ago)
Reply 2912
Avatar for Dim0nIX
Dim0nIX
Original post by wilsea05
it was quite clearly 1st order as half life was more or less constant. if you look at the graph it took 190s to half first time, but if you look where the crosses are the one nearest is actually slightly more to the right, so it probably is 200s, then it was 400s, and then at just after 600s

if it was 2nd order, it wouldn't have anywhere near a constant half life really.


Hey :smile: we are just discussing it. No need to get too emotional :wink: I drew tangents at regular time intervals and plotted a new graph of rate-concentration (wasted lots of time but I wanted to double check). The graph was a curve. That clearly implies second (or third) order. HOWEVER as you said the half-life was almost constant and my curve was only slopping up a little bit. This as many people are saying might be due to experimental error. We were probably expected to think outside the box and assume that half-life is constant (which I think is unfair). I hope that we atleast get some method marks if second order is wrong.
Reply 2913
Avatar for Dim0nIX
Dim0nIX
Original post by imperial maniac
Well thank the flying spaghetti monster for that.


Was it the flying spaghetti monster that enlightened you as to what order the reaction was with his holy appendage?
(edited 12 years ago)
Reply 2914
Avatar for Dim0nIX
Dim0nIX
Original post by PedalBrain
Enthalpy/entropy was surely + + for ice/water question??


Yep. Solid - liquid Entropy increases. Energy is needed to break the bonds in the lattice (ice) so energy needs to be put in so delta H is +
Original post by Dim0nIX

Original post by Dim0nIX
Hey :smile: we are just discussing it. No need to get too emotional :wink: I drew tangents at regular time intervals and plotted a new graph of rate-concentration (wasted lots of time but I wanted to double check). The graph was a curve. That clearly implies second (or third) order. HOWEVER as you said the half-life was almost constant and my curve was only slopping up a little bit. This as many people are saying might be due to experimental error. We were probably expected to think outside the box and assume that half-life is constant (which I think is unfair). I hope that we atleast get some method marks if second order is wrong.


Sorry it is definitely first order. Look into the book again the shape of the curve matches with first order curve as well. If it was to be 2nd order the gradient of the curve would look steeper and hence doesn't match with the book.Also as a physics student i knew that when determining whether the half life is constant it varies by 5 to 10% sometimes.
anybody else feel like they have worked their arses of all year to try and get an A, and it has all been wasted because of OCR and MAGIC TANG?!
Original post by Dim0nIX
Was it the flying spaghetti monster that enlightened you as to what order the reaction was with his holy appendage?


Indeed it was, I was looking at the exam, and his noodly appendage was inserted into my ear, giving me the gift of chemistry enlightenment.
Reply 2918
Avatar for Dim0nIX
Dim0nIX
Original post by terry_2006
Sorry it is definitely first order. Look into the book again the shape of the curve matches with first order curve as well. If it was to be 2nd order the gradient of the curve would look steeper and hence doesn't match with the book.Also as a physics student i knew that when determining whether the half life is constant it varies by 5 to 10% sometimes.


Interesting... I am a physics student as well and that is the first time I hear about variable half-life. In the chemistry book it explicitly said constant half-life implies first order.
what was the KOH electrolyte question??
where we were given two pka values and we had to write equations??
what did everyone put?!
xx

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