Edexcel Chemistry Unit 5 June 19 2012

Original post by James A

Guys!

I have a question.

I just looked at a question in a past paper that says

'explain what effect recrystallization has on the final yield of the product'

The answer says . 'decreases yield as some product remains in solution'

wtf, what solution? Is it talking about the solution that passes through the filter paper?

ahhhh at last a question

well u remember the part where we filter cold the filtrate is the solution they refer to and has a little bit of the compound in it and the soluble impurities .....

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ok peeps siging off now !!! love yaaaaa !!!!

Reply 583

Cyber123

Original post by battycatlady

In advance, it's pretty dire, but wth, it helps me remember complex ion colours :P If you don't know the tune, listen to cauliflowers fluffy first!

V2+ is purple, V3+ is green,
4+ is bluer than any I've seen
5+ is yellow and all zinc's white
Cu2+ is blue day or night
Fe3+ is yellow, Fe2+ is green
and Mn2+ has a pink sheen, and Mn2+ has a pink sheen, yeah!

For the solid hydroxides, Fe3+ is brown,
the nickel one's greener than any around
the copper one's blue and magenese brown
iron(2) is green when it's out on the town
The chromium's green, aliminium white
And they're all gonna have a party tonight, they're all gonna have a party tonight, yeah!

That's all I've got so far :P

I know it's dumb, but it's the only way I can learn stuff like this :P
Sorry if I've got any of the colours wrong, just change them :P

Wow, that made me laugh after a long day of revision and despair, just what I needed hahahaha :biggrin:

Reply 584

Original post by wam-bam

me know .... but they're both bonds to a carbon ... not different functional groups???

yes but those c atoms continue on so the groups attached are different

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F1's Finest

21

Original post by King_Arthur

ahhhh at last a question

well u remember the part where we filter cold the filtrate is the solution they refer to and has a little bit of the compound in it and the soluble impurities .....

So which solution are we referring to?

The hot solution that we filter off?

Or the cold solvent solution?

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Original post by King_Arthur

ahhhh at last a question

well u remember the part where we filter cold the filtrate is the solution they refer to and has a little bit of the compound in it and the soluble impurities .....

are you talking about when we filter it off using buchner funnel ..?!

Reply 587

wam-bam

1

Original post by King_Arthur

yes but those c atoms continue on so the groups attached are different

but it's a ring :confused:

p.s sorry for the continued confuzzlement, any minute now i'm going to get it ..... well..... hopefully

Reply 588

ksryiovulna356

Original post by Ellee123

fluorine can hydrogen bond with nitrogen oxygen and fluorine...
try this website
http://revisea2withme.wikispaces.com
or
http://reviseaswithme.wikispaces.com

the AS one has loads more on IMF

I know,but this is a flouride ION. It's got a full negative charge, while normal fluorine is just electronegative. It's basically a negative ion attracted to a positive dipole, as a pose to a negative ion attracted to a positive ion, or a positive dipole attracted to a negative dipole. O_o

Reply 589

Original post by wam-bam

but it's a ring :confused:

p.s sorry for the continued confuzzlement, any minute now i'm going to get it ..... well..... hopefully

whats so confusing wam bam ??!?!?!??!@
they asked circle around a chiral carbon !!! why would you circle a bond ! bonds arent chiral !! they are long ,short, double, triple but definitely not chiral !!!!!

Reply 590

ksryiovulna356

Original post by battycatlady

In advance, it's pretty dire, but wth, it helps me remember complex ion colours :P If you don't know the tune, listen to cauliflowers fluffy first!

V2+ is purple, V3+ is green,
4+ is bluer than any I've seen
5+ is yellow and all zinc's white
Cu2+ is blue day or night
Fe3+ is yellow, Fe2+ is green
and Mn2+ has a pink sheen, and Mn2+ has a pink sheen, yeah!

For the solid hydroxides, Fe3+ is brown,
the nickel one's greener than any around
the copper one's blue and magenese brown
iron(2) is green when it's out on the town
The chromium's green, aliminium white
And they're all gonna have a party tonight, they're all gonna have a party tonight, yeah!

That's all I've got so far :P

I know it's dumb, but it's the only way I can learn stuff like this :P
Sorry if I've got any of the colours wrong, just change them :P

*Hugs*

Say 2 then :smile:

Original post by James A

So which solution are we referring to?

The hot solution that we filter off?

Or the cold solvent solution?

i dont get this when we filter it off hot we allow it to cool right ?
then we filter it off again using a buchner funnel ??! WA ??!! and when do we wash it with cold solvent ??!

Reply 593

Original post by James A

So which solution are we referring to?

The hot solution that we filter off?

Or the cold solvent solution?

cold solvent and also as lesian said during suction filtration(that is buchner funnel)

Reply 594

Ellee123

Original post by iesians

thats the thing haunting me !
my treacher gave a lengthy method of hybridisation to find it
but ive come to know that if ligands are different ie :- 2 are CN- and 2 are CL- then the geometry is planar
if all four are CL- then ITS 100% TETRAHEDRAL!
and if all 4 are CN- then strangely its square planar !
i dunno the scientific reasoning behind it !

just been told this 'it will say in the question something like 'has geometric isomers' if it's square planar. if it doesn't you assume that it is tetrahedral'

Reply 595

Original post by iesians

i dont get this when we filter it off hot we allow it to cool right ?
then we filter it off again using a buchner funnel ??! WA ??!! and when do we wash it with cold solvent ??!

go read the RE-CRYSTALLIZATION PROCEDURE I POSTED EARLIER

the buchner funnel comes in suction filtration

Reply 596

F1's Finest

21

Original post by King_Arthur

cold solvent and also as lesian said during suction filtration(that is buchner funnel)

ahhh, so as it is hot, you pour it through the buchner funnel?

sorry for asking these questions, im confused lol

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