ID Number: Lab Partner: Note:
Chem 162 Experiment #2: Electrochemistry
All sections of this
report, except the
structural formulas,
must be typed.
Total Points = 60 (10 notebook, 50 report)
By signing below, you certify that you have not falsified data, that you have not plagiarized any part of this lab
report, and that all calculations and responses other than the reporting of raw data are your own independent
work. Failure to sign this declaration will result in 5 points beind deducted from your report score.
Signature:
Data and Calculations
Part I: Standard Potentials
Standard Potentials vs. Silver/Silver Chloride Reference Electrode
Cell Number Potential, V Cathode Anode
vs. Ag/AgCl Electrode Electrode
(spontaneous rxn)
1 (Ag) 0.554 Ag/AgNO3 Ag/AgCl
2 (Zn) -0.748 Ag/AgCl Zn/ZnNO3
3 (Pb) -0.363 Ag/AgCl Pb/Pb(NO3)2
4 (Cu) 0.139 Cu/Cu(NO3)2 Ag/AgCl
8 pts
Spontaneous Reaction
(between each half cell and Ag/AgCl reference)
Cell #
1 Ag+(aq) + Cl-(aq) ---> AgCl(s)
2 2AgCl(s) + Zn(s) ---> Zn2+(aq) + 2Ag(s) + 2Cl-(aq)
3 2AgCl(s) + Pb(s) ---> Pb2+(aq) + 2Ag(s) +2Cl-(aq)
4 2Cu2+(aq) + 2Ag(s) + Cl-(aq) ---> Cu(s) + 2AgCl(s)
Using the data from Table 2.1 in the lab manual, type the calculation for the expected Eo value for the Cu2+/Cu -
Ag/AgCl cell.(3 pts)
Cu2+(aq) + 2e- Cu(s) 0.34V
2Ag(s) + 2Cl-(aq) 2AgCl(s) + 2e- + -0.22V
Cu2+(aq) + 2Ag(s) + 2Cl-(aq) Cu(s) + 2AgCl(s) Eo = 0.12V
Based on your measured potential for this cell and the literature value for the standard reduction potential for the
Ag/AgCl reference electrode, what would you expect the overall potential to be for the spontaneous reaction between
your Cu2+/Cu electrode and a standard hydrogen eletrode? Type your calculation for the expected standard reduction
potential vs the SHE as well as the % error between this value and the literature value. (3 pts)
standard reduction potential of Ag/AgCl - literature value = +0.22 V
measured overall Eocell (Ag/AgCl and Cu/Cu 2+) = +0.139 V
expected standard reduction potential of Cu/Cu2+ = 0.139V + 0.22V = 0.359V
expected overall potential between Cu2+/Cu and SHE = 0.359V + 0.000V = 0.359V
% error = l (experimental - theoretical) l / theoretical
Zinc (#2) and Lead (#3) Ecell, V
Expected Ecell (V) based on YOUR Eo values Actual value of your measurement (V)
0.385 0.376
4 pts
Oxidation Half-reaction: Pb(s) ---> Pb2+(aq) +2e-
Reduction Half- reaction: Zn2+(aq) + 2e- ---> Zn(s)
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