3 AMIRAH NAJIHAH BINTI AZMAN.pdf - CHM578/674 2020...

CHM578/674 2020
Experiment 1: Galvanic Cell (20 marks)
Name: Amirah Najihah Binti Azman ID: 2020974033 Group: AS2223A1
(Refer Lab manual Exp. 1 CHM674 prior to answering the following Post-Lab Questions)
A: Galvanic Cell - Reduction Potentials of Several Half Cell Couples (9 marks)
1. Complete the following table with your interpretations from the galvanic cells.
Galvanic
Cell
Measured
E
cell
Anode Equation for
Anode Reaction
Cathode Equation for
Cathode Reaction
Cu - Zn +1.04 V Zn Zn → Zn
2+
+ 2e Cu Cu
2+
+
Cu - Fe +0.72 V Fe Fe → Fe
2+
+ 2e Cu Cu
2+
+
Zn - Fe +0.30 V Zn Zn → Zn 2+ + 2e Fe Fe 2+ + 2e
Write the overall equations for the three cell reactions.
2e → Cu
2e → Cu
→ Fe
1
2. Arrange the three half cells in order of decreasing (measured) reduction potentials. List the
reduction potential for each half cell couple relative to that of the Zn
2+
(0.1 M)/Zn couple,
which is – 0.79 V. Use a table of standard reduction potentials and the Nernst equation to
calculate the reduction potentials for each of these half
–
cell couples.
1
]
1
V
1
]
1

CHM578/674 2020
B: Effect of Concentration Changes on Cell Potential (6 marks)
1. Cell potential of ‘concentration cell’ : 0.045V
Anode reaction : Cu → Cu 2+ +
Cathode reaction: Cu 2+ + 2e → Cu
Explain why a potential/voltage was recorded.
2e
2