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AQA CHEM5 A2 Chemistry - 19th June 2013

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Reply 540

AspiringDoctor

Original post by itssochaotic

that's amazing, thank you so much!!! really appreciate it.

Many thanks to Tullia!
Happy revising for med school! :biggrin:

Reply 541

HaQ_mAn_

HOw the hell do you memorise all the colours of the complex ions?

Reply 542

Chewy29

Original post by HaQ_mAn_

HOw the hell do you memorise all the colours of the complex ions?

I go through them every morning once I wake up and every evening when I go to sleep. Weird I know but the repeating the process works for me. :smile:

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Reply 543

kocaadam

has anyone done the A2 chemistry EMPA exam on this bordeaux stuff and would be willing to give me some useful tips :biggrin:

would make my day

Reply 544

teen1234

Original post by laurawoods

Still I think that it is important to not talk about units, but talk about chemistry! Unit 4 has definitely got some important stuff in it...but yes, I do agree with you that those are easy to forget concepts and are not the absolute 'underlying' concepts! :smile:

One day , our teacher (he has a phD in chem) was saying that when he came into teaching, he couldn't remember any of it! So yeah, what u are saying makes perfect sense. Things like thermodynamics etc are good chem but not essential chem and inevitably people (even the best chemists) will forget it! If u don't mind me asking what did u get in the chem 4 unit?

A grade

Reply 545

laurawoods

Original post by itssochaotic

I have an offer from plymouth :smile:

Well done!

Reply 546

Jesss9

Has anyone done the born-haber cycles questions on the a-levelchemistry site (5.1 exercise 2)? I keep getting the wrong answer and have no idea where I'm going wrong!! :s

Reply 547

mackie0088

I think im being stupid but why does the color change in dichromate equilibrium when the oxidation state remains +6?

Is it something to do with the acidity or the ligands?

Thanks :smile:

Reply 548

mackie0088

Original post by Jesss9

Has anyone done the born-haber cycles questions on the a-levelchemistry site (5.1 exercise 2)? I keep getting the wrong answer and have no idea where I'm going wrong!! :s

Did you divide the bond dissociation by 2? Only one cl is needed not 2

Reply 549

JenniS

did the Jan paper as a mock today, it was such a nice paper, wish I'd sat that one!

Reply 550

popnit

Original post by JenniS

did the Jan paper as a mock today, it was such a nice paper, wish I'd sat that one!

Even the data book stuff??

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Reply 551

Jesss9

Original post by mackie0088

Did you divide the bond dissociation by 2? Only one cl is needed not 2

Oooh... no I didn't!! Seems really obvious now, thank you so much!! :tongue:

(edited 10 years ago)

Reply 552

JenniS

Original post by popnit

Even the data book stuff??

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there was only two 1 markers on that, think I got the one that was something to do with water, but all the transition metal and electrochemical cell stuff was alright

Reply 553

erniiee

Original post by mackie0088

I think im being stupid but why does the color change in dichromate equilibrium when the oxidation state remains +6?

Is it something to do with the acidity or the ligands?

Thanks :smile:

The colour change is because you have produced a different ion. The dichromate ion has a different structure (different number of ligands as well as 2 chromiums in dichromate) to the chromate ion, so there is a colour change when you produce the other complex.

Remember - dichromate (orange) is stable in acidic solution while chromate (yellow) is stable in alkaline solution.

Reply 554

Folks

Redox is the last chapter I need to wrap my head around and no matter what I do, I keep getting questions wrong! As soon as I think I understand the rules seem to change! :frown:

Reply 555

Sherlockedd

Original post by folks

redox is the last chapter i need to wrap my head around and no matter what i do, i keep getting questions wrong! As soon as i think i understand the rules seem to change! :frown:

ugh same mate it's so ugh-y :l

Reply 556

coolstorybrother

How far are you guys with your revision? Just want to know where I am/should be roughly against some others :smile:

(Not that great i dont think tbh :L)

Reply 557

dizzy17

how do you draw a square planar complex? And when drawing the tetrahedral and octahedral complexes, do we draw them with the different lines that we used in unit 1 when drawing shapes out, like the bold and dashed lines , or do we just use normal lines?