Unformatted text preview: ging them in order from most negative potential to most
We have treated the Cu2+/Cu couple as a reference point for our measurements. However, the standard
hydrogen electrode (SHE) is defined by international convention as the zero volt reference. The reduction
potential of Cu2+/Cu is +0.34 V relative to this standard. Therefore by adding +0.34 V to each of the
potentials you measured vs Cu2+/Cu will convert them to potentials vs SHE. Enter these values in Data
Table B2, column 3.
Refer to the table of Standard Reduction Potentials given on the inside front cover of this lab manual to
find the actual standard reduction potentials of these four couples. Enter these values in Data Table B2,
Table B1: Cell Potentials vs a Cu2+/Cu Couple
Table B2: Cell Potentials in Order, with Half- Reactions
Que s tion 9: Based on the order obtained by experiment,
Which species has the highest energy filled or partially filled orbitals?
Which species has the lowest energy unfilled or partially filled orbitals?
Which species is the strongest reducing agent?
Which species is the strongest oxidizing agent?
Que s tion 10: Using the order you found in Data Table B2 for the cell potentials, write the half- reaction for each
half- cell. Write the reactions as reductions.
Que s tion 11: The Mg2+/Mg couple was not tested when measuring half- cell potentials. Based on its behavior in
Part A, where would you place it in Data Table B2? (If you are doing Part B first, return to this question after
completing both parts of the lab.)
Before leaving, go to a computer in the laboratory and enter your results in the In- Lab assignment. If all
results are scored as correct, log out. If not all results are correct, try to find the error or consult with your
lab instructor. When all results are correct, note them and log out of WebAssign. The In- Lab assignment
must be completed by the end of the lab period. If additional time is required, please consult with your lab
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