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Topic: Redox reactions  (Read 5217 times)

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Diddy

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Redox reactions
« on: May 03, 2006, 10:47:15 AM »
Hello,

I have these two Redox Reactions:

C2H5OH + HCrO4- --> Cr3+ + CH3COOH

And the other one

HCrO4- + 2I- --> Cr3+ + I2

Both acid solutions.

Please help me as it is a very urgent matter.

Thanks

Offline Borek

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Re: Redox reactions
« Reply #1 on: May 03, 2006, 11:00:15 AM »
http://www.chembuddy.com/?left=balancing-stoichiometry&right=half-reactions-method

Try and show your work, someone will push you in the right direction.
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Diddy

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Re: Redox reactions
« Reply #2 on: May 03, 2006, 11:09:38 AM »
I am not that good at chemistry so I do often have problems. And as this is a very urgent report, I would really appreciate some help.

I can make the charges fit.

But not the number of Hydrogens atoms, they should be equally many on both side of the reaction arrow.


Diddy

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Re: Redox reactions
« Reply #3 on: May 03, 2006, 12:15:37 PM »
Oh come on it is very urgent.

I really do not have much time left.

Offline xiankai

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Re: Redox reactions
« Reply #4 on: May 04, 2006, 08:18:55 AM »
this is a short summary of the process in balancing redox reactions in acidic medium

1. split into two half-reactions (one with the element being oxidised and the oxidised element), (one with the element reduced and the reduced element)

2. balance elements (except for H or O)

3. balance H by adding H+

4. balance O by adding H2O

5. balance charges by adding e-

6. multiply the half-reactions by a number so that the e- present in the reduction rxn = e- present in the oxidation rxn.
 
so if reaction A has 2 e- and reaction B has 5 e-, multiply all the substances in A by 5 and B by 2, to get 10 e- total.

7. add the half-reactions together, cancel out the e- (you should have 0 e-, else go back to step 6.) cancel out any substances that appear on both sides equation.

8. done
one learns best by teaching

Offline Borek

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Re: Redox reactions
« Reply #5 on: May 04, 2006, 09:45:13 AM »
this is a short summary of the process in balancing redox reactions in acidic medium

Don't bother, if the OP was not interested in reading similar explanation pointed to by my link, instead asking for ready and fast answer, your summary is a waste of time. Unfortunate waste of time I must add.
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