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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: daveh on November 04, 2009, 06:53:45 AM

Title: Help please - lab due today - Impact on VOLTAGE when diluting anode solution
Post by: daveh on November 04, 2009, 06:53:45 AM

So I did an experiment with the following cell: Zn(s) | Zn+2 (aq, .5M) || Cu (s) | Cu+2 (aq, .5M) When I diluted the cathode solution (Cu+2) to 0.005M, I saw a slight drop in the measured voltage (1.080V undiluted, 1.030V diluted cathode). Is this what is supposed to happen?

What would happen to the measured voltage specifically if the anode solution (Zn+2) was diluted instead? And why?

I've been searching the web for days until I ran into a similar but different discussion in this thread here: http://www.chemicalforums.com/index.php?topic=31631.0

The other thread talks about molar conductivity being related to electrolyte concentration. However, I'm not sure how conductivity (units S/m) would relate to voltage exactly, so the other thread isn't of much help.

Title: Re: Help please - lab due today - Impact on VOLTAGE when diluting anode solution
Post by: Borek on November 04, 2009, 07:33:30 AM

You have not heard about Nernst equation?

Title: Re: Help please - lab due today - Impact on VOLTAGE when diluting anode solution
Post by: daveh on November 04, 2009, 07:36:28 AM

Quote from: Borek on November 04, 2009, 07:33:30 AM

You have not heard about Nernst equation?

Aaaah okay, I understand. You're a lifesaver. And no, we haven't talked about the nernst equation yet in class.