posted by Anonymous .
Calculate the value of Ecell for the reaction of cobalt(II) chloride and zinc metal, given the specific concentrations listed.
Zn(s) | Zn2+(0.21 M) || Co2+ (0.21 M) | Co(s)
Okay, so I keep getting -1.04 and -1.06 when I do this problem. I have used log k=-nEcell/0.0592 and then this other method i found where it told me to do something like K=0.0295/nxln
Please tell me what im doing wrong!
What did you use for Eo Zn and Eo Co?
I don't know why you have anything with k since k is not given.
Using -0.762 for Zn and -0.28 for Co, I obtained about 0.48v for Ecell.
EZn = EoZn -(0.0592/2)*log(1/0.21) = about -0.78; then note that this is in the cell as an oxidation so change that to +0.78v
ECo = -0.28 -(0.0592/2)*log(1/0.21) = about -0.30.
Then Ecell = Eox + Ered = 0.78-0.30=0.48v
Check my work.