Yahoo Answers is shutting down on May 4th, 2021 (Eastern Time) and the Yahoo Answers website is now in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.
Chemistry Homework Help?
The voltage generated by the zinc concentration cell described by,
Zn(s)|Zn2 (aq, 0.100 M)||Zn2 (aq, ? M)|Zn(s)
is 18.0 mV at 25 °C. Calculate the concentration of the Zn2 (aq) ion at the cathode
If you can answer thank you because I can not get it.
1 Answer
- FernLv 77 years ago
Zn =⇒ Zn+2(0.10) + 2e- (anode)
Zn+2(?M) + 2e- === Zn(s) (cathode)
Zn + Zn+2(?M) ===⇒ Zn+2(0.10) + Zn
E = E^o -0.0592 log Q; in this case E^o is zero.
E = - 0.0592 /n logQ where n is the number of electrons transferred, in this case n = 2
18 mV x 1 volt/1000mv = 0.018 Volts
0.018 = -0.0592 / 2 log(0.10) / [Zn+2]
0.018 = -0.0296 { log 0.10 – log [Zn+2] }
0.018 = -0.0296{ -1 - log[Zn+2]
0.018 = +0.0296 + 0.0296log[Zn+2]
-0.0116 = 0.0296log[Zn+2]
-0.39= log[Zn+2]
[Zn+2] = 10^-0.39 = 0.407 Molar
