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Ccea chemistry A2 unit 1 2016 victims thread

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Reply 20
Avatar for CERC
CERC
10
Original post by Mr.bob
What was your saponification value?
Runs cleaf--->all the fat had been hydrolysed
Ethanol as a solvent------>potassiim hydroxide dissolves more readily?


what did you get for the dilution factor in the multiple choice? i got an answer of 120cm3.

what did your friends think of it. mine said it was absolutely horrible, but none of them left out any, unlike like me!

Also, could you get the question where it was like draw the 11-Z-88-Z-23-Z.......Isomer?
Reply 21
Avatar for Mr.bob
Mr.bob
OP
16
Original post by CERC
what did you get for the dilution factor in the multiple choice? i got an answer of 120cm3.

what did your friends think of it. mine said it was absolutely horrible, but none of them left out any, unlike like me!

Also, could you get the question where it was like draw the 11-Z-88-Z-23-Z.......Isomer?


I think the numbers in the 8z-5z thingy related to the position of the c=c but i didnt have time to work out the exact config of groups to form Z-sterioisomers but hopefully ill get a mark for the c=c's.

The multiple choice answer i screwed up by not saying how much to ADD instead i just circled the answer for how much water was needed total :/.

People found it really hard at my school as well which is what you want to hear :colone:
I thought it was a rather straight forward paper except for all the calculations in the actual paper. I got lucky that I learnt the process of Kd which is pretty harsh for others considering it's not on the practical document or the spec doesn't mention you need to learn it unlike all the other procedures.


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Reply 23
Avatar for Mr.bob
Mr.bob
OP
16
Original post by CERC
what did you get for the dilution factor in the multiple choice? i got an answer of 120cm3.

what did your friends think of it. mine said it was absolutely horrible, but none of them left out any, unlike like me!

Also, could you get the question where it was like draw the 11-Z-88-Z-23-Z.......Isomer?


Did you remember to take the new value for volume away from the original volume for that multiple choice question
(edited 7 years ago)
Reply 24
Avatar for CCG88
CCG88
1
Original post by Mr.bob
3.33mg or something like that?

I think I got 140.1mg, didn't think it was right 😩
Reply 25
Avatar for CCG88
CCG88
1
Original post by CERC
couldnt agree with you more!

I felt like i'd been slapped in the face!!!

That question with the cyanoethanote seemed to go on for ages!!!


Yeah it really did. I don't think I even finished it
Reply 26
Avatar for CERC
CERC
10
Original post by CCG88
Yeah it really did. I don't think I even finished it


yeah, but i bet the questions you did were correct! I rushed them all trying to finish them and my calculations were all wrong!!!

anyway, it was all the drawing you had to do and the questions were really wordy!

were you able to get the equation for the cyanoethanoate and potassium cyanide and then liberating it with HCL? I spent ages on it thinking i had loads of time for everything else.....and i still didnt get it in the end.


do you think if you got a high A last year, a C or D in that paper and maybe like an A in the next one you could get still get an A overall?
Reply 27
Avatar for CCG88
CCG88
1
Original post by CERC
yeah, but i bet the questions you did were correct! I rushed them all trying to finish them and my calculations were all wrong!!!

anyway, it was all the drawing you had to do and the questions were really wordy!

were you able to get the equation for the cyanoethanoate and potassium cyanide and then liberating it with HCL? I spent ages on it thinking i had loads of time for everything else.....and i still didnt get it in the end.


do you think if you got a high A last year, a C or D in that paper and maybe like an A in the next one you could get still get an A overall?


Don't worry, I messed it all up too. Rushed answers, didn't get that equation, total nightmare. I was gutted because I had properly revised hard and for what ? 😩 It really wasn't like any other paper. Last year you needed 480 marks overall for an A so I would say yes you could. Say you had 240 marks from last year, and this year got full marks in practical, that would mean you would need 170 marks between each paper to get an A overall.
Reply 28
Avatar for Mr.bob
Mr.bob
OP
16
Original post by TomFitness
I thought it was a rather straight forward paper except for all the calculations in the actual paper. I got lucky that I learnt the process of Kd which is pretty harsh for others considering it's not on the practical document or the spec doesn't mention you need to learn it unlike all the other procedures.


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Howmany portions did you divide the solvent into? Also did mention anything on extracting the solute after dissoolving in whatever solvent was used?
Reply 29
Avatar for CERC
CERC
10
Original post by Mr.bob
Howmany portions did you divide the solvent into? Also did mention anything on extracting the solute after dissoolving in whatever solvent was used?


i divided it into two 25cm3 portions and then i said that you evaporated off the cyclohexane.

this test is actually giving me nightmares. i cant get over it! my motivation for the next one has dropped so much, because i revised so much and for what? LOL

what did you do for the decaryboxylation equation?
did you just reduce it to an alcohol or did you remove the -COOH altogether?
Reply 30
Avatar for CERC
CERC
10
Original post by CCG88
Don't worry, I messed it all up too. Rushed answers, didn't get that equation, total nightmare. I was gutted because I had properly revised hard and for what ? 😩 It really wasn't like any other paper. Last year you needed 480 marks overall for an A so I would say yes you could. Say you had 240 marks from last year, and this year got full marks in practical, that would mean you would need 170 marks between each paper to get an A overall.


same, i made sure to revise for that test a bit everyday even when other exams were coming up (like english or biology), i made notes and did the past papers twice and felt confident that i would definitely do well because i was fairly confident going in........but then i opened the paper :angry:

what do you think the next one will be like? harder or the same?

did any of your teachers say anything about it, hopefully mine wont say that it was doable because then i know i have definitely failed!
Reply 31
Avatar for CCG88
CCG88
1
Original post by CERC
same, i made sure to revise for that test a bit everyday even when other exams were coming up (like english or biology), i made notes and did the past papers twice and felt confident that i would definitely do well because i was fairly confident going in........but then i opened the paper :angry:

what do you think the next one will be like? harder or the same?

did any of your teachers say anything about it, hopefully mine wont say that it was doable because then i know i have definitely failed!


I seriously hope this next one is better. I'm not expecting it to be easy but I just hope it's not a complete nightmare. Well Ive been doing this chemistry in a night class at Belfast met, class finished last week so I don't know what my tutor thought about it :frown: I might email her and ask lol. Let me know what your teachers say anyway, might give me some hope :h:
Reply 32
Avatar for Mr.bob
Mr.bob
OP
16
Original post by CERC
i divided it into two 25cm3 portions and then i said that you evaporated off the cyclohexane.

this test is actually giving me nightmares. i cant get over it! my motivation for the next one has dropped so much, because i revised so much and for what? LOL

what did you do for the decaryboxylation equation?
did you just reduce it to an alcohol or did you remove the -COOH altogether?


Removedthe cooh altogether to get co2 what about you?
Reply 33
Avatar for CERC
CERC
10
Original post by Mr.bob
Removedthe cooh altogether to get co2 what about you?


yeh, i got that as well! my friend reduced it back to an alcohol which made me kind of worried! :colondollar:

what did you say for the enthanolic KOH question? i think i said something like it caused an elimination reaction but i think thats wrong!!!
Original post by CERC
yeh, i got that as well! my friend reduced it back to an alcohol which made me kind of worried! :colondollar:

what did you say for the enthanolic KOH question? i think i said something like it caused an elimination reaction but i think thats wrong!!!


I completely reduced it too. For ethanolic I think it was that the ethanol was used as a solvent to dissolve fat. For the solvent extraction I forgot too put it into multiple extractions but I'm hope I've got enough points that I'll only lose one mark max😑 what did people get for the pKa value if you remember?


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Reply 35
Avatar for CERC
CERC
10
Original post by TomFitness
I completely reduced it too. For ethanolic I think it was that the ethanol was used as a solvent to dissolve fat. For the solvent extraction I forgot too put it into multiple extractions but I'm hope I've got enough points that I'll only lose one mark max😑 what did people get for the pKa value if you remember?


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i completely messed it up! i dont think i used the equation properly so i got Ka first and then got pKa from that :K:

i think i got like 0.9 or something but that has to be wrong!

what did you say why iodine would not react with unsaturated solution but bromine water??
Original post by CERC
i completely messed it up! i dont think i used the equation properly so i got Ka first and then got pKa from that :K:

i think i got like 0.9 or something but that has to be wrong!

what did you say why iodine would not react with unsaturated solution but bromine water??


Can't remember what I wrote it was an educated guess that sounded right at the time but it might not be. I'm really hoping I can ace A2 2 and my AS resits which I'm very confident for!


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For the Ka you read the graph at 12.5cm3, giving a pKa of just under 2.6 then Ka is 10^-(2.58). For the Iodine one I put that Bromine is more reactive so it's faster and more likely to add across a c=c bond.
Reply 38
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Mr.bob
OP
16
Original post by Nathanbh321
For the Ka you read the graph at 12.5cm3, giving a pKa of just under 2.6 then Ka is 10^-(2.58). For the Iodine one I put that Bromine is more reactive so it's faster and more likely to add across a c=c bond.


Why 12.5 and not 25?
Reply 39
Avatar for B Smyth
B Smyth
1
I got 2.6 also for pKa because the question said the mid-point of the titration. I still don't know if that's right though.


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