Chemical Forums

Chemistry Forums for Students => High School Chemistry Forum => Topic started by: NYM on April 05, 2008, 01:14:10 PM

Title: Determine [Ag+] in an electrochemical cell
Post by: NYM on April 05, 2008, 01:14:10 PM

An electrochemical cell consists of a Zn electrode in 0.200 M Zn²⁺ (aq) and a Ag electrode in 0.100 M Ag⁺ (aq).
KCl (s) is added to the Ag electrode. E is measured to 1.04 V and E^o is 1.56 V. Determine [Ag⁺].


Nernst equation:
E = E^o - 0.059 V/2 * log ([Zn²⁺]/[Ag⁺]) =>
1.04 V = 1.56 V - 0.059V/2 * log (0.200/[Ag⁺]² =>
[Ag⁺] = 6.87*10^-10 M.

The right answer is 7.36*10^-10 M. What am I doing wrong here?

Title: Re: Determine [Ag+] in an electrochemical cell
Post by: LQ43 on April 05, 2008, 02:49:51 PM

Quote from: NYM on April 05, 2008, 01:14:10 PM

Nernst equation:
E = E^o - 0.059 V/2 * log ([Zn²⁺]/[Ag⁺]) =>
1.04 V = 1.56 V - 0.059V/2 * log (0.200/[Ag⁺]² =>
[Ag⁺] = 6.87*10^-10 M.

The right answer is 7.36*10^-10 M. What am I doing wrong here?

recalculate using 0.0592

Title: Re: Determine [Ag+] in an electrochemical cell
Post by: NYM on April 05, 2008, 03:43:23 PM

Quote from: LQ43 on April 05, 2008, 02:49:51 PM

Quote from: NYM on April 05, 2008, 01:14:10 PM

Nernst equation:
E = E^o - 0.059 V/2 * log ([Zn²⁺]/[Ag⁺]) =>
1.04 V = 1.56 V - 0.059V/2 * log (0.200/[Ag⁺]² =>
[Ag⁺] = 6.87*10^-10 M.

The right answer is 7.36*10^-10 M. What am I doing wrong here?

recalculate using 0.0592

D'oh! Thank you for pointing that out :D