I bloody hope not

Although if you go here I'm pretty sure it mentions that halfway through the document
https://chemrevise.files.wordpress.com/2022/01/14.-redox-edexcel.pdf

(edited 10 months ago)

Reply 89

hhhhheeeee

12

Original post by Pxnyl_

I bloody hope not

Although if you go here I'm pretty sure it mentions that halfway through the document
https://chemrevise.files.wordpress.com/2022/01/14.-redox-edexcel.pdf

ahh thank you sm🤞

Reply 90

OllieAS345

8

Original post by hhhhheeeee

does anyone know if we have to know why these link😟
4D1691D3-5E55-48E2-8381-FC64516DE448.jpg.jpeg

Yes but not like this.
You ovi need to know about E Cell values
You need to know S tot = S system + S surroundings
Need to know Delta G = Enthalpy Change - S system x Temperature(in Kelvin)
Need to know Delta G = -RTln(K)

Reply 91

diiana123

5

how is everyone feeling
im terrified

Reply 92

Abc12371

6

Original post by TypicalNerd

Because I'm in a generous mood, I have made some practice papers for you lot to use in your revision (note that I will NOT be making any more of these, because of how time consuming it is to do so - if you want more practice papers, you may have to make your own and I'd recommend using google docs if that is ever the plan).

Pages 1 - 24 on papers 1 and 2 are the question papers. Anything beyond that is the MS.
Pages 1 - 32 on paper 3 are the question paper and anything beyond that is the MS.

Disclaimer: these are NOT predicted papers or even remote attempts to guess what will actually come up. Anything that is not assessed on these practice papers could come up, so do not make these the entirety of your revision.

Erratum notice for MS on Q4(c)(ii) paper 3:

Spoiler

Thanks. Do you mind explaining why the concentration of chromium sulfate is not equal to the concentration of the acid? Don’t think I’ve ever seen a weak acid calc like this

Original post by Abc12371

Thanks. Do you mind explaining why the concentration of chromium sulfate is not equal to the concentration of the acid? Don’t think I’ve ever seen a weak acid calc like this

Chromium(III) sulphate is Cr2(SO4)3 - that means per mole of it dissolved, there are two [Cr(H2O)6]^3+ ions that form in solution.

So [hexaaquachromium(III)] = 2 x [Cr2(SO4)3]

Reply 94

Abc12371

6

Original post by TypicalNerd

Chromium(III) sulphate is Cr2(SO4)3 - that means per mole of it dissolved, there are two [Cr(H2O)6]^3+ ions that form in solution.

So [hexaaquachromium(III)] = 2 x [Cr2(SO4)3]

So 1 Cr3+ ion in Cr2(SO4)3 = 1 [Cr(H2O)6]^3+? And 1 Cr(H2O)6 complex ion produces 1 H+ ion shown by the equation?

Reply 95

user927401

8

i am so scared

Original post by diiana123

how is everyone feeling
im terrified

Reply 96

TypicalNerd

18

Original post by Abc12371

So 1 Cr3+ ion in Cr2(SO4)3 = 1 [Cr(H2O)6]^3+? And 1 Cr(H2O)6 complex ion produces 1 H+ ion shown by the equation?

2 Cr^3+ ions are present in 1 Cr2(SO4)3. Both of these chromium ions pick up water ligands upon dissolution.

Therefore each Cr2(SO4)3 makes two [Cr(H2O)6]^3+ complexes, which each act as monoprotic acids.

Reply 97

fawsa

13

why's it not MgBr2? (it's MgCl2)

(edited 10 months ago)

Screen Shot 2023-06-11 at 9.53.15 PM.png64.4KB

Reply 98

Abc12371

6

Thanks, did you make these questions yourself or are they from old spec papers?

Original post by TypicalNerd

2 Cr^3+ ions are present in 1 Cr2(SO4)3. Both of these chromium ions pick up water ligands upon dissolution.

Therefore each Cr2(SO4)3 makes two [Cr(H2O)6]^3+ complexes, which each act as monoprotic acids.