Chemistry Unit 6B [6CH08][Edexcel][International Candidates][22.05.2012]

OP

Original post by areyousure?

I'm doing it. No idea how to prepare for it though :frown:

They don't have a specification for this right?
I am going to do the past papers and then remember stuff like flame tests, reflux/distillation/recrystalization, hydroxide precipitates etc

I read somewhere that there was a hess diagram in 3B this time, I wonder what they are going to ask in 6B, electrochemical cells? lol

Reply 3

Misslassenza

5

i hope it goes all well

Reply 4

k121op

4 days left to prepare from scratch(i mean do QP and go through revision notes!)....still got to at least 4 yrs Unit 6B Chem QP,4yrs of Chem U2 QP(sitting for AS and A2 together :cool:

).....and fininsh off the remaining 2 yrs QP of BIO Unit 1.
How am i supposed to finish all of it in just 4 days?do u think it's possible?? :confused:

Reply 5

OP

Original post by k121op

4 days left to prepare from scratch(i mean do QP and go through revision notes!)....still got to at least 4 yrs Unit 6B Chem QP,4yrs of Chem U2 QP(sitting for AS and A2 together :cool:

).....and fininsh off the remaining 2 yrs QP of BIO Unit 1.
How am i supposed to finish all of it in just 4 days?do u think it's possible?? :confused:

Try to finish the question papers, if you can't answer a question use the mark scheme instead of wasting time on it (remember you have 4 days).

If you feel that you won't be able to make it in time, just read the questions & answers, so you at least see all types of questions before the real exam.

I have only one 6B paper left, and I will start that paper right after posting this message :P and then re read notes and experiment pages in the ****ty edexcel book xD

Reply 6

sevenbooks

1

Do you think we'll need to know mechanisms for Unit 6?

*freaking out :angry:

*

Reply 7

OP

Original post by sevenbooks

Do you think we'll need to know mechanisms for Unit 6?

*freaking out :angry:

*

I would advice you to check the SN1 and SN2 mechanisms from unit4. They may suddenly ask it in an experiment to determine the order of a reaction.

I am not edexcel but here is my answer, don't blame me later xD ;

You don't exactly need mechanisms of unit4 and 5 (like drawing benzene rings etc.) but of course you should know the reactions and what the products, reactants are (and it's always the best to know everything xD lol).. For example, in one paper the procedure is for making an ester which is a topic from unit 4 and in another one for making an azo dye, which is a topic from unit 5. If you don't understand what happens during the instructions, you may have problems while ansering the questions later.

In short, if you mean "knowing and drawing mechanisms" like in unit4 and 5, no it's not needed.

But again, I am not edexcel and they can decide to ask a mechanism, lol

(edited 11 years ago)

Reply 8

sevenbooks

1

Original post by Yorrap

I would advice you to check the SN1 and SN2 mechanisms from unit4. They may suddenly ask it in an experiment to determine the order of a reaction.

I am not edexcel but here is my answer, don't blame me later xD ;

You don't exactly need mechanisms of unit4 and 5 (like drawing benzene rings etc.) but of course you should know the reactions and what the products, reactants are (and it's always the best to know everything xD lol).. For example, in one paper the procedure is for making an ester which is a topic from unit 4 and in another one for making an azo dye, which is a topic from unit 5. If you don't understand what happens during the instructions, you may have problems while ansering the questions later.

In short, if you mean "knowing and drawing mechanisms" like in unit4 and 5, no it's not needed.

But again, I am not edexcel and they can decide to ask a mechanism, lol

Thank you so much! :biggrin:

I'll just read through everything. So far, in the past papers (new specification) they haven't asked for the mechanisms.

They could this year though! :eek:

...I hate paranoia.

Reply 9

OP

Original post by sevenbooks

Thank you so much! :biggrin:

I'll just read through everything. So far, in the past papers (new specification) they haven't asked for the mechanisms.

They could this year though! :eek:

...I hate paranoia.

Well, seems like there was a hess diagram in the last 3B paper xD

So I don't know what to expect, lol.

(edited 11 years ago)

Reply 10

sammy_93

Hellooo,
Don't they usually ask questions on transition metals, aldehydes and ketones, rates of equilibria as well as arenes?n I also saw something on actyl chlorides in one of the papers.
*panicking as well*
Please post revision notes as well as any other tips for chemistry

Reply 11

OP

Did you guys do any experiments for this unit in the school?

Reply 12

demdil

i'm taking the exam too :/ is there any old syllabus papers for this exam? where can i find them?

Reply 13

Gosh I wish I could find something to help revise the colors of the Transition metals and their oxidation states. :frown:

I always forget some!

Reply 14

OP

Original post by Otlichno

Gosh I wish I could find something to help revise the colors of the Transition metals and their oxidation states. :frown:

I always forget some!

You don't need to know "ALL" oxidation states, if I am not mistaken.

just the common ones, 2+/3+ like hydroxide percipitates.

again, did you guys do any experiments for this unit?

Reply 15

DeadBullyMafiosi

9

Anyone knows colouts of the complex ions of chromium ions ? I am confused :s-smilie:

Reply 16

demdil

Original post by Yorrap

You don't need to know "ALL" oxidation states, if I am not mistaken.

just the common ones, 2+/3+ like hydroxide percipitates.

again, did you guys do any experiments for this unit?

we didnt do any experiments at school for this. Now i will start to solve the past papers.. :/ i'm worried though..

Reply 17

Vanadium:

(V) is yellow
(IV) is blue
(III) is green
(II) is lavender

Chromium:

(III) is green
(VI) is yellow in CrO4 2- and orange in Cr2O7 2-
(II) is blue

Manganese:

(II) is pale pink
(VI) is deep green
(VII) is purple
(IV) is a brown solid.

Iron:

(II) is pale green
(III) is yellow in solution

Cobalt:

(II) Hydrated is red and anhydrous is blue.
(III) is red

Nickel:

(II) is green

Copper:

(II) is blue or green in CuCl4 2-
(I) is white
CuCO3 is green
CuO is black
Cu2O is red
[Cu(NH3)4] 2+ is deep blue
[Cu(RNH2)4] 2+ is deep blue (R can be any ligand).

Reply 18

Complexes with Sodium Hydroxide:

Mg 2+ and Ca 2+ white ppt, insoluble in excess
Al 3+, Zn 2+ and Pb 2+ give a white ppi, soluble in excess
Cu 2+ blue ppt that turns black on warming
Ni 2+ light green ppt insoluble in excess
Fe 2+ dirty green ppt, turns brown on standing
Cr 3+ greyish green ppt soluble in excess giving a deep green solution
Fe 3+ foxy red ppt
Mn 2+ beige ppt turns brown on standing
Co 2+ blue ppt that turns grey

Reply 19