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AQA CHM5/6 - Killer Papers Or What!!

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alisa

What's oxalate? I think I did it wrong, don't worry. I realised i'd left it out right at the end and just saw something that looked like 'en'(it had lots of CH2's and N's :confused:

), so I tried to draw it quickly. It was very rushed so probably wrong.

oxalate = ethandioate
someone tell me i havent done it wrong pleaseeeeeeeee lol i need as many marks as i can get!

Reply 21

Neel25

i thought that was one of the worst chm5 papers! i went thru all the past papers, n they did have some difficult questions, but 2days papers was much harder. i think the only good part was the mechanisms in section B..
as for chm6.. jus a typical multiple choice paper.. some tricky stuff, but not alot different from past papers..
well jus gota hope for the best now!

Reply 22

croakly

Module 5 was okay, they had many organic questions which made it simple. The only thing I forgot how to do is the partial pressure question, the calculation bit. I couldnt find the parial pressures of the 2 so couldnt do the calculations. So lose 4 marks there.

I am a bit annoyed that they didn't ever since ask any colour changes.

The synoptic paper was hard, maybe because I didnt really revised it. Its so easy to lose marks on it so the only result I am worried about is synoptic...

Reply 23

kesso12

was it aluminium hydroxide? lol

woops, i put AL2CO3+6HCL=2ALCL3+3HCL

Reply 24

alisa

Can anyone remember what they got for the partial pressures and the % of Fe question?

Reply 25

croakly

I think I got 96.1% if I remember for the iron, couldnt get the parial pressure...

Reply 26

alisa

I ended up with 4MPa and 12MPa for partial pressures. I think I got the % of Fe wrong.

Reply 27

Kernel

I get 4 and 12 for the PPs, and 96.1% rings a bell.

Reply 28

alisa

Damn I wonder where I went wrong on that!

Edit - Actually now I think of it, I may have gotten an answer like that, I remember thinking it was a big percentage. I wish I could remember what I put now.

Reply 29

kesso12

wooohoo, that's wht i got :biggrin:

happy chappy

Reply 30

alisa

I loved the autocatalysis question in section B with Mn²⁺/Mn³⁺ I was hoping that would come up.

Reply 31

Scipio

I did Al(OH)3 + NaOH --> NaAl(OH)4 and
Al(OH)3 + 3 HCL --> AlCl3 + 3H2O

First shows it can act as a acid, second as a base

Did anyone think there was a mistake in section B of module 5? It asked to show mechanism of Chlorine reacting with an alkane to form an haloalkane. Surely it meant alkene? Didn't work to that assumption though, so I guess I lost those 3 marks.

I though module 6 was pretty easy, only 2-3 tough questions I found.

Reply 32

Kernel

Oh and for the structure of the Chromium thing, I'm fairly certain it was a Cr³⁺ surrounded by 3 of whatever diamine it was, with the lone pair on the N being donated- which answers the next question of why is the enthalpy change approx. 0- its because the same number and type of bonds are being broken and formed (both N:->Cr³⁺).

EDIT:

Pav27

Did anyone think there was a mistake in section B of module 5? It asked to show mechanism of Chlorine reacting with an alkane to form an haloalkene. Surely it meant alkene?

No, I don't think so, the mechanism is Free Radical Substition (you need UV light to do it).

Reply 33

Scipio

Kernel

No, I don't think so, the mechanism is Free Radical Substition (you need UV light to do it).

Oh, *******s.

Reply 34

kesso12

Pav27

lmao, exactly wht i thought, until my friend told me otherwise, 3 marks though

kes

Reply 35

alisa

I did the free rad substitution thing, did you just have to write the equations?

i.e. Cl2 ----> 2Cl*

CH4 + Cl* ---> CH3* + HCl

CH3* + Cl* ----> CH3Cl

Reply 36

croakly

Pav27

I did free radicals reaction, where cl2 is split to cl* and that reacts with ch4 to form ch3*
where ch3* react witth cl* to form ch3cl an haloalkane

i also thought they got it wrong, but i thought about it :smile:

Reply 37

rustynator

Yeh...I found the partial pressures one really hard...and I am sure they are usually easy!! I ended up with 4 and 12MPa for the partial pressures...does that sound right??

For the amphoteric aluminium hydroxide I put ---> [AL(OH)4]^1- but I couldnt think of the acid reaction......was it ---> AlCl3

Also it was a right of sun of a b*tch to draw that Cr with the 3 bidentate amine ligands! What did everyone put for the organic products with the Cr2O7^2-?.....I put a carboxylic acid for the reflux one and an aldehyde for the other.

Reply 38

alisa

rustynator

Yeh...I found the partial pressures one really hard...and I am sure they are usually easy!! I ended up with 4 and 12MPa for the partial pressures...does that sound right??

For the amphoteric alumin hydroxide I put ---> AL(OH)4]^1- but I couldnt think of the acid reaction......was it -----> AlCl3

Also it was a right of sun of a b*tch to draw that Cr with the 3 bidentate amine ligands! What did everyone put for the organic products with the Cr2O7^2-.....I put a carboxylic acid for the reflux one and an aldehyde for the other.