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Chemistry Exams 19/06/06

Reply 60

Clearvision

Haha Prometheus did you get 100%?

Reply 61

Prometheus

lol no, i messed up the writing about the C==O/C==C bond because i said they were both subject to nuceuphilic attack (and also described one of the mechanisms as nucleophillic when it should have been electrophilic). And im sure i've made lots of other stupid mistakes.

Reply 62

gfdsa

Prometheus

Conditions not standard (i.e. in the car battery its gonna be hot cos of heat from engine)

damn ,should have went with my brain and not my guts . i wrote that the H(+) increases the electrical conductivity of the electrolyte thus higher E value

Reply 63

lesmes

hey in my class we all seemed to get 15% for the iron question... but suppose its wrong. Anyone REALLY hates chemistry and is REALLY happy of having finished it? (even though we still have the sypnotic to go....)

for the A+ 3B i wrote electrolic addistion, the 2,4 DNP thing, i think it was a test for aldehydes/ketones and a red precipitate was formed. C==O forms permanent dipole... can attract things.. C==C just opnes double bond to form new bonds...

VERY DIFFICULT PAPER THOUGH... glad there was a q. on recrystallisation....
Drive Fast Car ForWarD -->
D= Dissolve in hot solvent,
F= filter preheated fluted funnel
C= cool
F= Refilter using buchner funnel
W= Wash
D= Dry

Imperial--> Aeronautical Eng firm AAB
Loughborough ..> automotive eng. insurance AA

Reply 64

=Keith=

3

Im glad chemistry is kind of over but a little bit annoyed too. I some silly mistakes and besides even getting the answer, i crossed it..
Wat bout Kc in unit 4? Its jus me n smashing dude hu got 0.49? all the others got different answers in my class !
Do u guys knwo the grade boundaries? Is an A around 55 - 60 out of 75 !!! ??

Reply 65

yoyo87

lesmes

hey in my class we all seemed to get 15% for the iron question... but suppose its wrong. Anyone REALLY hates chemistry and is REALLY happy of having finished it? (even though we still have the sypnotic to go....)

for the A+ 3B i wrote electrolic addistion, the 2,4 DNP thing, i think it was a test for aldehydes/ketones and a red precipitate was formed. C==O forms permanent dipole... can attract things.. C==C just opnes double bond to form new bonds...

VERY DIFFICULT PAPER THOUGH... glad there was a q. on recrystallisation....
Drive Fast Car ForWarD -->
D= Dissolve in hot solvent,
F= filter preheated fluted funnel
C= cool
F= Refilter using buchner funnel
W= Wash
D= Dry

Imperial--> Aeronautical Eng firm AAB
Loughborough ..> automotive eng. insurance AA

A+3B i think its Sn2 nucleophilic/electrophilic addition
red precipitate Cu20 (copper I oxide) shows that it is an aldehyde homologous
C=0 electronegatity of oxygen atom greater so attracts pair of electrons to oxygen atom, so it becomes polar.

Reply 66

Prometheus

dunno hope so, n i've just realised i missread table in U5 on rate, so got A as second order and B as first instead of other way around. Hopefully ill get some error carried forward cos all the other questions on that question were based on that answer, otherwise in f-d in the a.

Reply 67

catherine2772

yeh, salters was a right pig. Was full of weirdo questions asked in strange roundabout ways!. I think i put [Fe(H2O)6]3+ for the red water ion - really didnt get that bit though!

Got the 0.910 or whatever it was..and the solution was unsuitable right? Didnt like the Tg question, or that titration one - i hadnt a clue!!!! and why paper chromatography?!? I thought chromatography was in CD?!

Reply 68

Misogynist

18

Prometheus

dunno hope so, n i've just realised i missread table in U5 on rate, so got A as second order and B as first instead of other way around. Hopefully ill get some error carried forward cos all the other questions on that question were based on that answer, otherwise in f-d in the a.

Haha, I almost fell for that. They changed the conc. of B first, and they asked the order of A first in the part. I ALMOST fell for that one.

Reply 69

catherine2772

oh, and for the ionic equation, did you guys do complexes, or just Fe3+ + 3OH- sorta thing? i want sure

Reply 70

mizfissy815

12

usman_s

Im glad chemistry is kind of over but a little bit annoyed too. I some silly mistakes and besides even getting the answer, i crossed it..
Wat bout Kc in unit 4? Its jus me n smashing dude hu got 0.49? all the others got different answers in my class !
Do u guys knwo the grade boundaries? Is an A around 55 - 60 out of 75 !!! ??

6.9 x 10^-4....

Reply 71

Misogynist

18

In that Kc question, Did you have to divide the number of moles at equilibrium by 20 dm^-3 to get the concentration and then calculate Kc?

Reply 72

Prometheus

In that Kc question, Did you have to divide the number of moles at equilibrium by 20 dm^-3 to get the concentration and then calculate Kc?

Yeh

Reply 73

mizfissy815

12

In that Kc question, Did you have to divide the number of moles at equilibrium by 20 dm^-3 to get the concentration and then calculate Kc?

Yes...

Reply 74

manthi

7

Yes, just like any other Kc calculation.

Reply 75

Misogynist

18

manthi

Yes, just like any other Kc calculation.

Just making sure, you dont need to die.

Reply 76

Prometheus

Arghhhhhh Edexcel keep tricking me, lets see how much they like it when i trick them into not thinking I've let a bear into their headquaters. (Yes, Edexcel have a headquarters)

Reply 77

manthi

7

What were the two reasons for using ethanoyl chloride to make an ester instead of ibuprofen? One reason is that it need not be heated, but whats the other?

Reply 78

manthi

7

Why

Just making sure, you dont need to die.

Eh? Didnt intend any offence there mate... :confused:

Reply 79

rhythm_bandit

11

guys this is so confusing.
they are talking about 3 exams on this thread and most ppl are not saying which one. i hope there's already a separate edexcel unit 5 one.

edit: yea there is.
allow this thread.

Chemistry Exams 19/06/06

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