Use graphing software plot E cell vs. ln([Fe2+]/[Fe3+]) for the three cell measurements in part 4. Determine the equation of the best fit line. E cell (volts)ln([Fe2+]/[Fe3+])
0.319 0
0.248 2.3
0.411 -2.3
2) From the best fit line calculate the value of n for the overall reaction.
Ecell = -(RT/nF) lnQ + Eocell
where Y = E cell, m=slope = -RT/nF, x = lnQ, and b = y-int = Eo cell
3) Based on the intercept associated with the best fit line, calculate the standard reduction potential for the Fe2+/Fe3+ half cell. Remember that the Eocell obtained form the graph is for the entire cell where Eocell = ECu, ox+ EoFe(III),red and EoCu, ox = -0.34 V. Determine a percent error based on the cited Fe(III)/F(II) reduction potential of +0.77V