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Topic: Half Reaction Paradox- *delete me*  (Read 2532 times)

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Offline BenMullin

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Half Reaction Paradox- *delete me*
« on: October 02, 2010, 10:57:04 PM »
Hey everyone, I'm balancing a half reaction for chemistry, and I've gotten to the point where I'm multiplying the oxidation reaction and the reduction reaction by a coefficient to balance electrons on both sides. My problem is this: The oxidation half reaction has 7 electrons in it, and the reduction half reaction is already balanced for charge. How can I find the least common multiple of 7 and zero? The only solution seems to put a zero in front of the other half reaction. Here's the problem:

Br (-minus one)(aq) + I(-minus one)(aq) ====> Br2 + IO3 (-minus one)

And here's where I'm at:

Oxidation half reaction:
3H20 + 2Br (-minus one) + I (-minus one) ====> Br2 +IO3 (-minus one) + 6H+ + 7e-

Reduction half reaction:
H+ +HCLO =====> Cl (-minus 1) + H2O

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Re: Half Reaction Paradox- *delete me*
« Reply #1 on: October 03, 2010, 04:14:54 AM »
Neither of your half reactions is charge balanced.

What does it mean "charge balanced"?
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Offline BenMullin

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Re: Half Reaction Paradox- *delete me*
« Reply #2 on: October 03, 2010, 11:58:35 AM »
I think they're both balanced, though I could be wrong. With the oxidation reaction, there's 6 H+, one cation, and 7 electrons. Making a net charge of zero.

With the reduction half reaction, there's an H+ cation on one side and a Cl- anion on the other side, making a net charge of zero.

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Re: Half Reaction Paradox- *delete me*
« Reply #3 on: October 03, 2010, 01:37:37 PM »
No, charge balanced means the same charge on both sides of the equation. Doesn't matter if it is neutral, or -7 and -7, or +2 and +2 - what matters is that it stays identical.

Just like balance of atoms is effect of mass conservation, this is effect of charge conservation.
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Offline BenMullin

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Re: Half Reaction Paradox- *delete me*
« Reply #4 on: October 03, 2010, 02:35:22 PM »
*facepalm* thanks, man. After a couple of hours of staring at my own equation, the fact that +1 and -1 don't equal each other finally sauntered up and slapped me in the face.

Thanks for the help.

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