chem help needed! voltaic cells?

Question

A voltaic cell consists of an Mn/Mn2+ half-cell and a Pb/Pb2+ half-cell. Calculate [Pb2+] when [Mn2+] is 3.3 M and Ecell is 0.17 V.

Answer 1

Sorry I do not have the standard EMF table with me, but you can find the data easily for the Mn/Mn2+ half-cell and the Pb/Pb2+ half-cell from your text book, and hence get ΔEo. The calculation would be based on the formula:
ΔG = ΔGo + kT Ln Q
and ΔG = -nFΔE, therefore:
ΔE = ΔEo - (kT/nF) Ln Q
In this case you have ΔE = 0.17V, ΔEo from the book, k = 8.314J/K·mol, T is room temperature 298K, n = 2, and F the Faraday constant 96485 C/mol, thus you get Q and [Pb2+] can be found.