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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: hunter457 on November 08, 2009, 01:05:58 PM

Title: Balancing Redox Reactions
Post by: hunter457 on November 08, 2009, 01:05:58 PM

For both of these problems, I'm having trouble writing the half reactions. How do I know how many e^- to put and on which side of the equation do they go?

1. The following redox reaction occurs in basic aqueous solution. Balance it with the smallest whole number coefficients and determine the coefficient for the hydrogensulfate anion.

Al(s) + HSO₄^-(aq)  :rarrow: Al₂O₃(s) + S₂^-(aq)

2. The redox reaction below occurs in acidic solution. Balance it with the smallest whole number coefficients and determine the coefficient for H₂O.

Zn(s) + NO₃^-(aq) ---> Zn₂⁺(aq) + N₂O(g)

Title: Re: Balancing Redox Reactions
Post by: hunter457 on November 08, 2009, 10:02:16 PM

Actually, I figured out that you balance the atoms and then only add electrons to balance the charges on both sides of the equations.

So:

1) 3
2) 5

Is that right?

Title: Re: Balancing Redox Reactions
Post by: Borek on November 09, 2009, 03:30:35 AM

Looks OK, even if your formatting was confusing.