Edexcel Chemistry Unit 5 June 19 2012

Original post by nmudz_009

Okay, so what do you do with it next?

After using buchner funnel, add ice cold solvent to remove soluble impurities. Allow pure solid to dry and measure its melting temp. using a thermometer and compare with a data book, to see what compound its temp. is really close to.

Reply 382

Ai-

Hey guys

Do we need to know the colours of Cl complexes and reactions with carbonate?

(edited 11 years ago)

Reply 383

keerthi3

Can someone help me with jan 2010 question 22) (a) (iii)

why can't the reagents be lithiumaluminiumhydride in dry ether because George Facer book says those are the reagents :frown:

Reply 384

How do you guys know whether the electron config. of Mn 2+ is [Ar] 3d5 or [Ar] 3d4 4s1 or [Ar] 3d3 4s2. I know its the first option since i looked at the ms, but why is it that?

Reply 385

Original post by shahofiran

How do you guys know whether the electron config. of Mn 2+ is [Ar] 3d5 or [Ar] 3d4 4s1 or [Ar] 3d3 4s2. I know its the first option since i looked at the ms, but why is it that?

ok so the electron config of all the standard (not copper of chromium) transition metals fills up their 4s sub shells first before 3d so for manganese it is [Ar] 4s2 3d5
now for EVERY transition metal when they are ionised they lose their 4S elecrtons first so it is just [Ar]3d5

Reply 386

Original post by physics1

ok so the electron config of all the standard (not copper of chromium) transition metals fills up their 4s sub shells first before 3d so for manganese it is [Ar] 4s2 3d5
now for EVERY transition metal when they are ionised they lose their 4S elecrtons first so it is just [Ar]3d5

Thank you

What about in the case for copper and chromium?

Reply 387

Original post by shahofiran

Thank you

What about in the case for copper and chromium?

Copper is [Ar] 4s1 and 3d10 (it prefers to have a full 3d subshell)
Chromium is [Ar] 4s1 and 3d5 (prefers to have a half full 3d subshell)

Reply 388

lorry:)

20

NYAAAAHHHHHHHHHHHHHHH

so freakin scared for this one. it cannot go as badly as unit 4 did, it just cannot. :sigh:

Reply 389

Original post by physics1

Copper is [Ar] 4s1 and 3d10 (it prefers to have a full 3d subshell)
Chromium is [Ar] 4s1 and 3d5 (prefers to have a half full 3d subshell)

Thank you once again. What are you doing in terms of revision atm? I'm just going through the past papers with the ms.. to ''pick up'' essentially where i went wrong before and im going to go over a few things i find a bit tricky. What exactly are we expected to know for steam distillation?

Reply 390

Original post by laurie:)

NYAAAAHHHHHHHHHHHHHHH

so freakin scared for this one. it cannot go as badly as unit 4 did, it just cannot. :sigh:

i rly hope (possibly think) that the grade boundaries would be low for unit 4.. it was similar in terms of difficulty to jan 2010 unit 4.

Reply 391

areyousure?

13

Original post by laurie:)

NYAAAAHHHHHHHHHHHHHHH

so freakin scared for this one. it cannot go as badly as unit 4 did, it just cannot. :sigh:

I feel the same :s-smilie:

I could not even read the lattice energy correctly on the Unit 4 paper! Hopefully this one will be better :smile:

Best of luck !

Reply 392

Puloot

4

guys, what does coupling really means?

Reply 393

Original post by Puloot

guys, what does coupling really means?

joining together of two molecules each containing a benzene ring. They become like a ''couple'' lol as the name says.

Reply 394

Puloot

4

Original post by shahofiran

joining together of two molecules each containing a benzene ring. They become like a ''couple'' lol as the name says.

lol thanks! good luck for chem tomorrow! :smile:

Reply 395

Original post by Puloot

lol thanks! good luck for chem tomorrow! :smile:

np, thanks you too :smile:

Reply 396

Arusa01

Good luck guys! I'm not half prepared for this exam :P

Reply 397

Original post by shahofiran

Thank you once again. What are you doing in terms of revision atm? I'm just going through the past papers with the ms.. to ''pick up'' essentially where i went wrong before and im going to go over a few things i find a bit tricky. What exactly are we expected to know for steam distillation?

haha no worries... i finding helping others helps me see the gaps in my knowledge! revision im just going through the review exercise questions now! i find it hard to revise chemistry tho yeh.... basically why you would use steam distillation how it helps and the apparatus! what do you need for an A/A*?

Reply 398

aqua05

9

Can someone explain to me jan 2011 Q10 please? How do you which electrode to use & why??

Reply 399