Potential Difference CR pg. 49

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Kaitlin Ross 3E
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Joined: Fri Sep 25, 2015 3:00 am

Potential Difference CR pg. 49

Postby Kaitlin Ross 3E » Sun Jan 31, 2016 11:00 pm

When it says E(cathode)-E(anode)=E(cell) for the reaction with copper and zinc, the E(Cu)=0.34 and the E(Zn)=-0.76. Does the reaction and value for Zinc get flipped or would the values be plugged into the equation so the value would be 0.34-(-0.76)=1.1V?

Fariha Hameed 1D
Posts: 22
Joined: Fri Sep 25, 2015 3:00 am

Re: Potential Difference CR pg. 49

Postby Fariha Hameed 1D » Mon Feb 01, 2016 12:20 pm

You would plug the -0.76 V into the equation to get +1.1 V. The reason the equation is Eocell = Eocathode - Eoanode is that all Eo values are written as reductions, but since the anode (Zn in this case) is oxidized, the equation accounts for reversing the Eo value by subtracting it from the Eo of the cathode. Hope this helps!


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