You are Here: Home

# Equilibria, Energetics and Elements (F325) - June 2011 Exam. watch

1. (Original post by volvicstar)
what is the tetrahedral complex and what are the bond angles?
I think its Cu2+ with 4Cl-

bond angle 109.5
2. (Original post by asem93)
Susan did you get my message earlier?
yaaa dude u quoted me by acci no poroblemooo
3. (Original post by asem93)
Reactions involving Complex ions:

- Percipitation
- Substitution
- Redox

Any more?
Any chance you could give us the reactions, or tell us where to find them? Please.
4. (Original post by mandn)
half a mole of acid reacts with half a mole of a base this then forms it's conjugate base and water, but when using a whole mole of acid and half a mole of base half a mole of acid doesn't react and forms a buffer with the half mole of it's conjugate base
thanks !!!
5. Bond angle of square planar?
6. how does one write half equations from overall equations? whats an easy method...
7. (Original post by susan23)
WHAT THE ****!!! I DIDNT KNOW THAT!! looooooooooooooooooool

so what happens to the other half of the acid then??? reacts to form water?
A buffer solution is a solution of a weak acid and its conjugate base. It finds its own equilibrium depending on conditions. This is the acid disassociation constant, Ka.

HA (aq) <--> H+(aq) + A-(aq)
Ka =
[H+][conjugate base (represented by A-]
----------------------------------------------------
[Acid(represented by HA)]

When a small amount of acid is added the concentration of H+ increases. The equilibrium position shifts to the left, as the conjugate base reacts with MOST of the H+ ions to form the initial acid on the left hand side of the disassociation equation above.
When a small amount of an alkali is added concentration of OH- increases. MOST of these react with H+s already in the solution to form H2O, and more HA disassociates to restore pH
8. (Original post by INeedToRevise)
Bond angle of square planar?
90 degrees
9. (Original post by 123trident)
I'm confused, when deltaG<0, the reaction is spontaneous and hence stable, but in the mark scheme of the jan 11 paper it says deltaG>0 is stable. Why is this?
If DeltaG<0 then the reaction is spontaneous and the compound is therefore unstable.
If DeltaG>0, then the reaction is not spontaneous, and the compound is stable, since it won't react spontaneously!
10. Octahedral - 90 degrees bond angles.

What are the bond angles for tetrahedral and square planar?
11. (Original post by SteveScott)
A buffer solution is a solution of a weak acid and its conjugate base. It finds its own equilibrium depending on conditions. This is the acid disassociation constant, Ka.

HA (aq) <--> H+(aq) + A-(aq)
Ka =
[H+][conjugate base (represented by A-]
----------------------------------------------------
[Acid(represented by HA)]

When a small amount of acid is added the concentration of H+ increases. The equilibrium position shifts to the left, as the conjugate base reacts with MOST of the H+ ions to form the initial acid on the left hand side of the disassociation equation above.
When a small amount of an alkali is added concentration of OH- increases. MOST of these react with H+s already in the solution to form H2O, and more HA disassociates to restore pH
yeppp thank you very much!!
12. (Original post by asem93)
THIS!
im sorry whaaat?
13. (Original post by Twinkles)
Octahedral - 90 degrees bond angles.

What are the bond angles for tetrahedral and square planar?
tet - 109.5
square - 90 deg
14. (Original post by Amit619)
Any chance you could give us the reactions, or tell us where to find them? Please.
If you have the OCR Heinemann book

Page 207 (just learn the table)

Page 214-215 (Learn the 3 examples)

Page 218

BTW, I really recommend that everyone should learn the Redox of manganate with Iron example (literally parrot fashion)
15. how do we work out number of moles ?
16. I still cant write the rate determining step etc

FINGERS CROSSED IF ITS ON THE EXAM ITS NOMORE THAN 2 MARKS
im sorry whaaat?
I just wanted to reiterate, if anyone could explain the formation of 02 in the specimen paper...
18. (Original post by goldlock)
I'd learn the whole mess regarding thiosulfate titrations and the colour changes there, I have a hunch it might come up
What changes in colour are there with thiosulfate titrations?
19. Deduce the half-equation for the reaction that takes place at the positive electrode in a methanol fuel cell.
Jan 11
Some help me out pls
20. In cell potentials, why does the E potential increase for a copper half cell if you increase conc. of the Cu2+ ions? I know eqm shifts to the right due to le chatelier's principle, but why does the E potential increase? Electrons are being removed from the system right?

### Related university courses

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: December 10, 2012
The home of Results and Clearing

### 3,152

people online now

### 1,567,000

students helped last year
Today on TSR

Hang on, have Edexcel's come out already?

### University open days

1. SAE Institute
Animation, Audio, Film, Games, Music, Business, Web Further education
Thu, 16 Aug '18
2. Bournemouth University
Fri, 17 Aug '18
3. University of Bolton
Fri, 17 Aug '18
Poll
Useful resources

Can you help? Study Help unanswered threadsStudy help rules and posting guidelines

## Groups associated with this forum:

View associated groups

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE