CIE A Level Chemistry Paper 4

Hey

I swear it was the hardest paper I ever did. So freakin different ;-;

As for the cobalt question, my friend said you gotta write geometrical isomerism which indeed makes sense. However, I ended up writing cis trans. The other one I made was optical because it seemed similar to the one in book asides from Iodine of course :/

Any one get the balancing right?

Reply 4

very difficult... 10 questions!!! What on Earth is C4O6??? xDDD I found out that it was a cyclic di-ester after the exam it was impossible. The colors of Cobalt was very rare as well together with the two balancing equations in a row. The calculations were fine, the efficiency and the percentage by mass questions were OK and the coefficient of affinity question was dead easy. Organic was fine except for the reagent that unites two benzene and forms a ketone and the one of phenyalamine to phenol, I mysteriously got both of them correct though but i messed up the conditions to phenol.

In general it was extremely difficult to be honest, for raw mark i think a 75 approx. I'm sure they're gonna lower the grade boundaries by a LOT though.

Reply 5

Original post by ElPutoAmoH0ngjia

very difficult... 10 questions!!! What on Earth is C4O6??? xDDD I found out that it was a cyclic di-ester after the exam it was impossible. The colors of Cobalt was very rare as well together with the two balancing equations in a row. The calculations were fine, the efficiency and the percentage by mass questions were OK and the coefficient of affinity question was dead easy. Organic was fine except for the reagent that unites two benzene and forms a ketone and the one of phenyalamine to phenol, I mysteriously got both of them correct though but i messed up the conditions to phenol.

In general it was extremely difficult to be honest, for raw mark i think a 75 approx. I'm sure they're gonna lower the grade boundaries by a LOT though.

IKR why were there 10 questions laik what?
I couldn't realize it either. I wrote pink for cobalt color haha. Too bad it's wrong.

Calculations weren't hard but since I couldn't balance the two equations properly, I just hope they give me ecf for them :/

Can you tell what you used for reagents and all in that question?
I got the phenol question right. It was H20 with T>10C, no?

I feel sad that I left Nerst equation for later and couldn't complete it :/

Reply 6

Original post by Coloneltreavy

IKR why were there 10 questions laik what?
I couldn't realize it either. I wrote pink for cobalt color haha. Too bad it's wrong.

Calculations weren't hard but since I couldn't balance the two equations properly, I just hope they give me ecf for them :/

Can you tell what you used for reagents and all in that question?
I got the phenol question right. It was H20 with T>10C, no?

I feel sad that I left Nerst equation for later and couldn't complete it :/

Baaah I got all the conditions wrong hahaha. The Nerst was dead easy bro. for the phenol alkene like thing i put dichloromethanal which I dont think is correct hahaha

Reply 7

Original post by ElPutoAmoH0ngjia

Baaah I got all the conditions wrong hahaha. The Nerst was dead easy bro. for the phenol alkene like thing i put dichloromethanal which I dont think is correct hahaha

5 marks down the drain for conditions hm? ;-;
Man Nerst was easy but I wasn't sure if the equation is + or - >.> Yea I sucked at electrode potential shiz.
That is definitely wrong lol. Phenol is formed from Diazonium ion+H2O

Reply 8

God this exam was horrific. IKR the book didnt even have materials about making phneol. Also the color and structure of cobalt chloride, how is that 5 points??? Did I miss smt in class??

Btw, wil you get marks deducted for incorrect stuff when you have correct stuff before it, cuz e.g. I said +heat for alkylation of benzene when you don't need it but everything else was correct. Also I made a stupid spelling error, spelled Friedel as Fridel, really hope they won't deduct a point for that :tongue:

Reply 9

Original post by Powerofvoice

God this exam was horrific. IKR the book didnt even have materials about making phneol. Also the color and structure of cobalt chloride, how is that 5 points??? Did I miss smt in class??

Btw, wil you get marks deducted for incorrect stuff when you have correct stuff before it, cuz e.g. I said +heat for alkylation of benzene when you don't need it but everything else was correct. Also I made a stupid spelling error, spelled Friedel as Fridel, really hope they won't deduct a point for that :tongue:

The book actually stupidly hints it in reaction kinetics chapter. I would have never seen it if my teacher hadn't told me. I read through chemguide once so that helped I hope. Plus, this reaction was asked often in past papers.

wasn't it three points of color and structure ;o? I HOPE SO omg

I was talking about the different parts carrying marks. Like I got balancing wrong but I did the later parts correct which required me to balance it so I hope they give me those marks

Reply 10

Original post by Coloneltreavy

The book actually stupidly hints it in reaction kinetics chapter. I would have never seen it if my teacher hadn't told me. I read through chemguide once so that helped I hope. Plus, this reaction was asked often in past papers.

wasn't it three points of color and structure ;o? I HOPE SO omg

I was talking about the different parts carrying marks. Like I got balancing wrong but I did the later parts correct which required me to balance it so I hope they give me those marks

Omg I just found that in the book. But they also don't have hydrogenation of benzene to cyclohexane which is in the syllabus(or I didn't find it). And I saw it was 5 points cuz I remember myself wondering how am I supposed to get them. Anyways the grade boundaries are (hopefully) low.

And do you know anything about cie ignoring the wrong answer when the right answer is present, I really don't want to lose more points than I already did :'(

Reply 11

Original post by Powerofvoice

Omg I just found that in the book. But they also don't have hydrogenation of benzene to cyclohexane which is in the syllabus(or I didn't find it). And I saw it was 5 points cuz I remember myself wondering how am I supposed to get them. Anyways the grade boundaries are (hopefully) low.

And do you know anything about cie ignoring the wrong answer when the right answer is present, I really don't want to lose more points than I already did :'(

I was just checking the book for electrophoresis and thank God I got that right at least.

I remember there beign two parts to the question, no? The one with color and complex formula and i dont remember the second one. Do you?

I really hope the it is low man.

So the thing about cie ignoring it. Nope, they don't. They will only ignore it as long as it doesn't contradict with your correct answer. But this friend of mine got 22/60 raw marks in p2 last year and it was adjust to 46/60. I have no idea how or why, though. BUT I HOPE THEY DO IT AGAIN

Reply 12

Original post by Coloneltreavy

I was just checking the book for electrophoresis and thank God I got that right at least.

I remember there beign two parts to the question, no? The one with color and complex formula and i dont remember the second one. Do you?

I really hope the it is low man.

So the thing about cie ignoring it. Nope, they don't. They will only ignore it as long as it doesn't contradict with your correct answer. But this friend of mine got 22/60 raw marks in p2 last year and it was adjust to 46/60. I have no idea how or why, though. BUT I HOPE THEY DO IT AGAIN

I think the question was asked like this: State the colours(I remember it was plural) you would observe when blablabla. Write down the formulae of the complexes formed and descirbe their structure or smt like that, so yeah. And I also really hope they do that :tongue:

I'm going to lose so many marks tho because of stupid errors, and hopefully they see I tried hard haha

Reply 13

Also in the book they used deltaS(system)/deltaS(surroundings)/deltaS(total) but in the exam they only used deltaS, does anyone know which deltaS they referred to? I said a bit about both deltaS(sys) and deltaS(total) just to make a bit sure.

Reply 14

Original post by Coloneltreavy

5 marks down the drain for conditions hm? ;-;
Man Nerst was easy but I wasn't sure if the equation is + or - >.> Yea I sucked at electrode potential shiz.
That is definitely wrong lol. Phenol is formed from Diazonium ion+H2O

oh yeah i know that i was talking about the other question of organic, think i messed that one up. Do you remember? The one which begins with two benzene rings and then an ethyl bromine was connected etc etc xDD

Reply 15

Original post by Powerofvoice

Also in the book they used deltaS(system)/deltaS(surroundings)/deltaS(total) but in the exam they only used deltaS, does anyone know which deltaS they referred to? I said a bit about both deltaS(sys) and deltaS(total) just to make a bit sure.

Its usually delta S sys when they give you data. I guess because I've only seen 2 entropy questions of CIE, one today and one from specimen paper :?

Reply 16

Original post by Powerofvoice

Also in the book they used deltaS(system)/deltaS(surroundings)/deltaS(total) but in the exam they only used deltaS, does anyone know which deltaS they referred to? I said a bit about both deltaS(sys) and deltaS(total) just to make a bit sure.

I did it with respect to -TdeltaS since they didn't give us a deltaHr to work with. I dont know if it's right though. And damn man, the complex question was five marks ;-; just damn

Original post by ElPutoAmoH0ngjia

oh yeah i know that i was talking about the other question of organic, think i messed that one up. Do you remember? The one which begins with two benzene rings and then an ethyl bromine was connected etc etc xDD

Hmm i remember. I think you have to use fredial craft alkylation by C6H5COCl for the first step. The second one my friend added an alcohol group but i dont remember what I wrote. Then you can substitute the alcohol with bromine and then bromine to CN and that is reduced to COOH. I forgot most of the reagents though :biggrin:

Reply 17

Here I found the Co and Ni isomer strcture: https://en.wikipedia.org/wiki/Dichloridobis(triphenylphosphane)nickel(II)

And for Co(R3P)2I2, it is tetrahedral too, if you open the book to where Co ions are talked about, you see a small line of letters saying Co normally forms a tetrahedral ligand stucthre with anionic ligans(e.g. I-, Cl-, and so probably R3P-)

(edited 7 years ago)

Reply 18