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# AQA - Unit 5 - Energetics, Redox and Inorganic Chemistry watch

1. Woooo! In 7 hrs and 35 mins, we will be freeeeeeeeeeeeeeeeeeeee! :')
2. guys how would you react half equation for this equation Q7b

http://www.a-levelchemistry.co.uk/AQ...W-QP-Jun10.pdf thanx alot
3. (Original post by al_habib)
guys how would you react half equation for this equation Q7b

http://www.a-levelchemistry.co.uk/AQ...W-QP-Jun10.pdf thanx alot
From the question, we know that the emf of the reaction is +2.91 V.

Using the value from the table that Li+ + e- ---> Li = -3.04 V, we know that

E(positive electrode) - -3.04 = 2.91, that is, E(positive electrode) + 3.04 = 2.91.

2.91 - 3.04 = -0.13 V = E(positive electrode)
4. (Original post by Jin3011)
I'm not as prepared as I was for unit 4. So I think maybe 100ums If I'm lucky.
I good B probably. I wanted an A* overall but this exam clearly wasn't having it lol
5. Guys, look at the answer for 7c) in this mark scheme. http://www.scribd.com/doc/50819775/A...11-Mark-Scheme

It says [Al(OH)6]3- when NaOH is added in excess (QP- http://www.scribd.com/doc/50819577/A...y-January-2011 if you need)

In the textbook it says when you add OH- in excess you get [Al(OH)4]- (p243 of the official nelson thornes one)
6. I went to bed and just woke up...I wonder why

my 12:00 we'll be free from the bondage's of AQA!!
7. Which one is correct?
8. (Original post by T-Toe)
I went to bed and just woke up...I wonder why

my 12:00 we'll be free from the bondage's of AQA!!
I take it you didn't pick chemistry based subject at uni? I didn't. I won't ever see chemistry again in my life. Hopefully...
9. (Original post by joseph2008)
I take it you didn't pick chemistry based subject at uni? I didn't. I won't ever see chemistry again in my life. Hopefully...
LOL I did However it won't be endorsed by crappy AQA :P
10. (Original post by joseph2008)
Which one is correct?
My dad's a former chemist and insomniac. He says that [Al(OH)4]- should be produced, and that the mark scheme is incorrect (unless the question is a specific case that we aren't aware of)
11. (Original post by joseph2008)
Which one is correct?
I'd say stick with [AL(OH-)6]3-

I've learnt to not question AQA's mark schemes.. or they'll be price to pay lol
12. Where does it say on the mark scheme?
All I saw was [cr(oh)6]^3-
13. (Original post by Jin3011)
Where does it say on the mark scheme?
All I saw was [cr(oh)6]^3-
Talking to me?

6b)

EDIT: Sorry, I said the wrong question before, its 6b not 7c. Check out 6b.
14. Thats really awkward. All I've ever known is oh4 not oh6. Wikipedia says this Aluminium hydroxide is amphoteric. It dissolves in acid, forming Al(H2O)63+ (hexaaquaaluminium(3+)) or its hydrolysis products. It also dissolves in strong alkali, forming Al(OH)4- (tetrahydroxidoaluminate(1-)).
No mention of any oh6

But weirdly enough, they've got this http://www.wikichemistry.com/konfuci...nium+hydroxide

Why does everything have to contradict itself =[
15. (Original post by Jin3011)
Thats really awkward. All I've ever known is oh4 not oh6. Wikipedia says this Aluminium hydroxide is amphoteric. It dissolves in acid, forming Al(H2O)63+ (hexaaquaaluminium(3+)) or its hydrolysis products. It also dissolves in strong alkali, forming Al(OH)4- (tetrahydroxidoaluminate(1-)).
No mention of any oh6
Yup. I'm confused now. Which idiot puts one thing in their official book then something else in their own mark scheme?
16. (Original post by joseph2008)
Yup. I'm confused now. Which idiot puts one thing in their official book then something else in their own mark scheme?
I know. Those 1-2 marks could be the difference between a whole grade.
17. (Original post by Jin3011)
I know. Those 1-2 marks could be the difference between a whole grade.
I was looking at a sheet which my teacher personally wrote and photocopied. It says OH4. I'm gonna go with what she said.
18. (Original post by joseph2008)
Yup. I'm confused now. Which idiot puts one thing in their official book then something else in their own mark scheme?
AQA - proud to make students suffer, or possible just incapable of proof reading and complacently incompetent.

Just have to hope the question doesn't come up as I now have no idea which to put if it did. Oh well, at least it's nearly over.
19. (Original post by joseph2008)
I was looking at a sheet which my teacher personally wrote and photocopied. It says OH4. I'm gonna go with what she said.
I wrote oh4 in my mock and my teacher marked it wrong
And it's what she taught us as well.
20. this exam gonna be great, ill tell u lot my answers afterwards lol

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