# 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 Eo is 1.56 V. Determine [Ag+].

Nernst equation:
E = Eo - 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
Nernst equation:
E = Eo - 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
Nernst equation:
E = Eo - 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