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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: CheezeSlayer on September 04, 2012, 09:57:29 PM

Title: Balancing Net Ionic Equations Problem
Post by: CheezeSlayer on September 04, 2012, 09:57:29 PM

I'm having a hard time with this particular chemical equation that I am supposed to balance.

Cu(s)   + H + (aq) + NO3-(aq)   --> NO2(g)   + H2O(l) + NO3-(aq) + Cu2+(aq)

The instructions are the balance the Net Ionic Equation of this chemical equation. 

I know that in a properly balanced equation that no same species should appear on both sides of the reaction so I cancelled out NO3- on both sides and was left with:

Cu(s)   + H + (aq) --> NO2(g)   + H2O(l) + Cu2+(aq)

After balancing this equation my answer was:

Cu(s)   + 2H + (aq) --> NO2(g)   + H2O(l) + Cu2+(aq)

I'm not sure if this is correct, can someone please provide guidance?

Title: Re: Balancing Net Ionic Equations Problem
Post by: UG on September 04, 2012, 11:21:34 PM

Have you heard/learned about balancing redox half equations? You can balance this reaction using this method.

Title: Re: Balancing Net Ionic Equations Problem
Post by: Borek on September 05, 2012, 02:38:06 AM

Quote from: CheezeSlayer on September 04, 2012, 09:57:29 PM

I know that in a properly balanced equation that no same species should appear on both sides of the reaction so I cancelled out NO3- on both sides

That's not correct. That is, you are right that no species should end on both sides, but NO₃^- gets reduced to NO₂, so you can't remove before balancing.

Quote

Cu(s)   + 2H + (aq) --> NO2(g)   + H2O(l) + Cu2+(aq)

I'm not sure if this is correct, can someone please provide guidance?

Simple check - balanced reaction has the same number of atoms and the same total charge on both sides. Do you have the same number of atoms of oxygen and nitrogen on both sides?