Year 12s: what will be the first way you research your future options? >>

Aqa chem 4/ chem 5 june 2016 thread

Scroll to see replies

Reply 2260

420memeception69

When you got 6 hours sleep and youve got chem 5 n chill in 2 hours :'( :eek:

Reply 2261

Cakey_101

Original post by haj101

When it's giving out charge- discharge therefore you write the equation how it is..
When it's recharging flip the equation...

Wouldn't they be the same thing?
To work out the overall equation you use the anti-clockwise rule right?

Reply 2262

Cakey_101

Original post by haj101

When it's giving out charge- discharge therefore you write the equation how it is..
When it's recharging flip the equation...

Actually i think i know what you mean!
So discharging is when the cell is being used and recharging is the reverse when its being recharged.

Reply 2263

420memeception69

Original post by Cakey_101

Actually i think i know what you mean!
So discharging is when the cell is being used and recharging is the reverse when its being recharged.

Exactly

Reply 2264

Hopefulmedic15

Good luck everyone! :smile:

Reply 2265

Cadherin

Good luck to everyone! :smile:

Reply 2266

ixguard

Original post by Hopefulmedic15

It's still being oxidised from Co2+ ---> Co3+

If it's just in air it's:

[Co(NH3)6]2+ ===> [Co(NH3)6]3+ + e-

If it's in air its 4[Co(NH3)6]2+ + O2 + 2H2O ===> 4[Co(NH3)6]3+ + 4OH-

Reply 2267

sm78354

well went bad to worst now. Came early out of exams didn't know what to do in many parts

(edited 7 years ago)

Reply 2268

Fibsy

I found it mostly easy but I don't want to get my hopes up. The questions i didn't get were:
What is the effect on emf of increasing pressure of oxygen?
Ditto for effect of increasing Pt surface area
Conditions under which E for something was something (I put in circuit with standard hydrogen electrode with 298K etc)

For the titration calculation I out something like 96%? Sneaky of them to make the compound have three C2O4 ions in

Posted from TSR Mobile