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AQA AS-LEVEL chemistry unit 2, 23/05/2012, raw mark POLL AND MARKSCHEME

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Original post by iAre Teh Lejend
Yeahh, -49 and -399, and yes they did.


Wohoooooooooo :banana2:... but the rest arghhhhhh :eyeball::getmecoat:
I though it was Increase, but then though that it would shift to the left.. DAMN!!

I got -49 and then some random figure like 0.00393kg But I guessed for that one.
Original post by CheekiiMonkii
Wohoooooooooo :banana2:... but the rest arghhhhhh :eyeball::getmecoat:


:/
What was the original figure that needed dividing by the moles?
Reply 24
Avatar for enimpri
enimpri
2
I'm doing chemistry 2 tomorrow... Will it be the same exam?!
Original post by PineappleChristmas
I though it was Increase, but then though that it would shift to the left.. DAMN!!

I got -49 and then some random figure like 0.00393kg But I guessed for that one.


It was increase though ? :confused:
Original post by iAre Teh Lejend
It was increase though ? :confused:


Yeah it was increase, i just made a silly mistake.
Original post by PineappleChristmas
Yeah it was increase, i just made a silly mistake.


Ahhh unlucky mate :redface:
Reply 28
Avatar for Miyata
Miyata
2
Original post by iAre Teh Lejend
Yeahh, -49 and -399, and yes they did.


got same asnwers as you for all questions you mentioned. What was the questions and numbers for calculation with -49? I can't remember lol, I think I remember number -399 but can't recall what I got for another one. Well I am good with calculations and was confident so it should be right unless I wrote down a wrong value or entered into calculator, but I was careful so xD And only the last one, graph where the gradient was steeper reached same position as original, the first one stayed at the top and second below. First one was double the height of original, second was 40% of original one, so it was with the first line or so I think, can't remember, but I remember original curve had 100 volume and 1.0 concentration, while second had 100 volume and 0.4 concentration, so it was less than half.

yeah for -399 it was 140*4.18*7.5 then divide by 1000 then divide by 0.011 and then stick minus in front because it was exothermic and therefore answer is -399

But don't remember for the enthalpy the values.
(edited 11 years ago)
Original post by iAre Teh Lejend
:/


I noe right.... >.< ..... I didn't think I would do bad in chem...... :frown:
guys what did you put for the ionic questions. and did you find it as hard as i did i thought the questions were tough but i felt i got a few of them right. also for the question about saftery when making butan1,4 diol ? i was dissapointed there werent more marks for mechanisms.
Reply 31
Avatar for kimmar
kimmar
Original post by Miyata
got same asnwers as you for all questions you mentioned. What was the questions and numbers for calculation with -49? I can't remember lol, I think I remember number -399 but can't recall what I got for another one. Well I am good with calculations and was confident so it should be right unless I wrote down a wrong value or entered into calculator, but I was careful so xD And only the last one, graph where the gradient was steeper reached same position as original, the first one stayed at the top and second below. First one was double the height of original, second was 40% of original one, so it was with the first line or so I think, can't remember, but I remember original curve had 100 volume and 1.0 concentration, while second had 100 volume and 0.4 concentration, so it was less than half.

yeah for -399 it was 140*4.18*7.5 then divide by 1000 then divide by 0.011 and then stick minus in front because it was exothermic and therefore answer is -399

But don't remember for the enthalpy the values.


The question asked the enthalpy change of the methanol when 1 MOLE of it was combusted so after you got the -399 as the value, you then had to calculate it to get the enthalpy change when 1 mole was burnt so it was just ratio so the answer would have been much more exothermic...I swear?

I'm 100% sure that the question said in the second paragraph that what the enthalpy change was when 1 mole of methanol was combusted :P
yh i think it was -399 because it was i got tht and already divided it by 0.1 i think??
i was gutted felt i was gunna get an A as long as there wasnt much on ionic equations and learn behold ..
Reply 34
Avatar for Miyata
Miyata
2
Original post by kimmar
The question asked the enthalpy change of the methanol when 1 MOLE of it was combusted so after you got the -399 as the value, you then had to calculate it to get the enthalpy change when 1 mole was burnt so it was just ratio so the answer would have been much more exothermic...I swear?

I'm 100% sure that the question said in the second paragraph that what the enthalpy change was when 1 mole of methanol was combusted :P

No, you had q = 4389J or 4.389 kJ, and that is 0.011 mole. To get 1 one you divided 4.389 by 0.011 and you got 399, then coz its exothermic you stick a minus. But you can stick it before that as well, -4.389/0.011.
Reply 35
Avatar for Theteacake
Theteacake
Original post by iAre Teh Lejend
-399kJmol^-1 :smile:


****! I forgot to put minus :eek:
(edited 11 years ago)
Reply 36
Avatar for kimmar
kimmar
Original post by Miyata
No, you had q = 4389J or 4.389 kJ, and that is 0.011 mole. To get 1 one you divided 4.389 by 0.011 and you got 399, then coz its exothermic you stick a minus. But you can stick it before that as well, -4.389/0.011.


oh yeah true, i got -399 anyways so good :smile:
oi what about the ionic equations is any gunna put on an unofficial mark scheme on ??
what did you get for the le chantlieirs questions??
Original post by iAre Teh Lejend
How did everyone find it, please vote on the poll :biggrin:


easiest paper ever......defo 140 :colone:

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