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How do you deal with 3 given elements for a half reaction?

Posted: Sun Feb 05, 2017 6:42 pm
by Andrew Uesugi 3I
I'm honestly used to and fine with 4 elements being used, such as:

Reactant + Reactant -> Product + Product

However, there are times when I have a tough time with three.

For example,

Reactant + Reactant -> Product

or

Reactant -> Product + Product

These given amount of elements confuse me, seeing how I have no idea how to deal with these and how to use them for half reactions. Any tips?

Re: How do you deal with 3 given elements for a half reaction?

Posted: Sun Feb 05, 2017 7:14 pm
by Pauline Tze 3B
Hi Andrew,

Regardless of what equation you're being given, you need to identify which elements within those compounds are being oxidized/reduced and separate the oxidation/reduction reactions into two equations (at that point they will be unbalanced). You balance the elements (changing coefficients, adding water, hydrogen, or hydroxide as needed), then you balance the charges (add electrons as needed). Then you add both half reactions together.

If you're given a reaction with an odd number of compounds, it may be a little uncomfortable to work with, but you follow the same principle (just be aware that one compound can be BOTH the oxidizing and reducing agent and could be the reactant (or product) in both half reactions).

If you're still confused, just post a specific problem you're stuck on and I'm sure someone will help.