Algebraic method to balance redox equations


by diffrac
Tags: algebraic, balance, chemistry, equations, method, redox, redox balancing
diffrac
diffrac is offline
#1
Oct20-13, 04:39 AM
P: 9
Hi all,

I'm learning how to solve redox equations. I found the algebraic method to solve equations such as this one:
Fe[itex]^{2+}[/itex] + Cr[itex]_{2}[/itex]O[itex]_{7}[/itex][itex]^{2-}[/itex] +H[itex]^{+}[/itex][itex]\rightarrow[/itex] Fe[itex]^{3+}[/itex] + Cr[itex]^{3+}[/itex] + H[itex]_{2}[/itex]0
and i was able to solve it.

What I don't see is how to use that algebraic method to solve an equation without superscripts; since it doesn't allow you to balance the charges, right?
like for example: NaOH + Cr(OH)[itex]_{3}[/itex] + NaClO[itex]\rightarrow[/itex] Na[itex]_{2}[/itex]CrO[itex]_{4}[/itex] +NaCl + H[itex]_{2}[/itex]O

Thanks for your help.
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Borek
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#2
Oct23-13, 04:15 AM
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If everything is neutral (on both sides of the reaction) there is no need to separately balance the charge. But you can always write an additional identity

[tex]0\times a_1 + 0\times a_2 + ... = 0\times b_1 + 0\times b_2 + ...[/tex]

(assuming ai are stoichiometric coefficients on the LHS of the equation, and bi are coefficients on the RHS).

Compare ChemBuddy lecture on the algebraic method of reaction equation balancing - it shows how to balance both equations with charged and uncharged species.

Use [sub][/sub] and [sup][/sup] tags to format the formulas, don't mix normal text with LaTeX, it is not guaranteed to work OK.


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