Advanced Higher Chemistry 2012-2013

Can someone explain me when does a nucleophilic addition occur? Is it just when an aldehyde or a ketone reacts hydrogen cyanide to form cyanohydrins and that's it?

Reply 1781

I am Ace

4

Original post by deedee123

Anyone doing an all nighter/staying up late?

You mad bro?
You'd bomb the exam

Original post by Chemistry Help

like what? 1s 2s 2p 3s 3p 3d 4s??

And for other atoms are 1s 2s 2p 3s 3p 4s 3d no?

Or the opposite? :confused:

What Deedee said

Reply 1782

clivethestickman

Sorry to be a nuisance, it'll be the last question I promise :colondollar:

I understand that K = [NO]^2 [O2] / [NO2]^2 but no matter what I do I cannot fathom how they reach A as the answer. It's most likely a really silly mistake on my part (s'pose it comes with the territory of revising at ten before the exam :biggrin:

)

Reply 1783

GermanScientist

9

If someone uploads the paper tomorrow, quote me and I'll (try to) do the answers. Not saying they'll all be correct - if you spot a mistake in them, let me know and we'll sort it. :smile:

Reply 1784

deedee123

16

Original post by I am Ace

You mad bro?
You'd bomb the exam

What Deedee said

I'm not, i just noticed people were still on this thread at like 3am (much to their anger obviously after my negging :zomg:

)

Reply 1785

I am Ace

4

Original post by clivethestickman

Sorry to be a nuisance, it'll be the last question I promise :colondollar:

I understand that K = [NO]^2 [O2] / [NO2]^2 but no matter what I do I cannot fathom how they reach A as the answer. It's most likely a really silly mistake on my part (s'pose it comes with the territory of revising at ten before the exam :biggrin:

)

I can't make sense of this either

Reply 1786

deedee123

16

Original post by GermanScientist

If someone uploads the paper tomorrow, quote me and I'll (try to) do the answers. Not saying they'll all be correct - if you spot a mistake in them, let me know and we'll sort it. :smile:

can you take chemistry papers home? I can't remember for sure but i think you might write on the question booklet :frown:

Reply 1787

DarrenBoyle

10

Can anyone help explain to me why the answer is D and not B (I thought Cr would have less d-orbital electrons and therefore less likely to split the d-orbital and therefore less likely to be coloured)
colour transition metal.png

Reply 1788

I am Ace

4

Original post by Amiro123

Can anyone help explain to me why the answer is D and not B (I thought Cr would have less d-orbital electrons and therefore less likely to split the d-orbital and therefore less likely to be coloured)
colour transition metal.png

Haven't really looked at it, but it's probably something to do with Chromium not following the Aufbau

i.e it doesn't fill the 4s first and hence doesn't lose those elctrons first

Reply 1789

Chemistry Help

Original post by deedee123

I'm not, i just noticed people were still on this thread at like 3am (much to their anger obviously after my negging :zomg:

)

Uhm yeah but not before the day of the exam lol..

Reply 1790

Blue7195

7

Original post by GermanScientist

If someone uploads the paper tomorrow, quote me and I'll (try to) do the answers. Not saying they'll all be correct - if you spot a mistake in them, let me know and we'll sort it. :smile:

ahh thankyou so much! you've been a massive help these past few days

Reply 1791

Shengis14

13

Original post by Amiro123

Can anyone help explain to me why the answer is D and not B (I thought Cr would have less d-orbital electrons and therefore less likely to split the d-orbital and therefore less likely to be coloured)
colour transition metal.png

No, D has a full 3d subshell so the electrons cant have d->d transitions, so no colour

Reply 1792

Chemistry Help

Original post by I am Ace

Haven't really looked at it, but it's probably something to do with Chromium not following the Aufbau

i.e it doesn't fill the 4s first and hence doesn't lose those elctrons first

Check the d orbitals I think

Reply 1793

FeelingofSuccess

Original post by GermanScientist

If someone uploads the paper tomorrow, quote me and I'll (try to) do the answers. Not saying they'll all be correct - if you spot a mistake in them, let me know and we'll sort it. :smile:

That would be awesome! If I can, I'll take the paper home tomorrow and upload it :smile:

Aaah, I really hope the exam goes well!

Reply 1794

Chemistry Help

When does nucleophilic addition occur?

Reply 1795

TheFOMaster

13

Original post by I am Ace

You mad bro?
You'd bomb the exam

What Deedee said

Proof: I involuntarily done this for Higher Physics. I think I bombed that pretty hard.

Reply 1796

deedee123

16

Original post by Amiro123

Can anyone help explain to me why the answer is D and not B (I thought Cr would have less d-orbital electrons and therefore less likely to split the d-orbital and therefore less likely to be coloured)
colour transition metal.png

Doesn't Zn2+ have a full 3d shell and you need an incomplete d shell to be coloured?

i think this thread is MWI, the comments are all scrambled :lol: