Experiment #4

Experiment #4 - Discussion: In this experiment the...

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Discussion: In this experiment the reduction potentials of different metals were observed and then used to determine if the reaction was spontaneous or not. Then Avogadro’s number and Faraday’s constant were calculated through electrolysis using the metals’ half reduction reactions and observations that were made. In part one of the experiment the standard reduction potentials of metals relative to each other were measured. The cell potential is what drives electron flow in an electrochemical cell in a redox reaction. This can be measured and shown in the half- reactions. Measured standard reduction potentials at 25 ° C Half-reaction E°(v) ref. to H E°(v) ref. to Cu E°(v) ref. to Ag Ag + + e - Ag(s) 0.80 .381 0.0 Cu 2+ + 2e - Cu(s) 0.34 0.0 -.339 2H + + 2e - H 2 (s) 0.0 Not measured Not measured Fe 2+ + 2e - Fe(s) -0.41 -.781 -.663 Zn 2+ + 2e - Zn(s) -.076 -.657 -1.083 Actual standard reduction potentials at 25 ° C Half-reaction E°(v) ref. to H E°(v) ref. to Cu E°(v) ref. to Ag Ag + + e - Ag(s) 0.80 0.34 0.0 Cu 2+ + 2e - Cu(s) 0.34 0.0 -0.41 2H + + 2e - H 2 (s) 0.0 Not measured Not measured Fe 2+ + 2e - Fe(s) -0.41 -0.630 -.76 Zn 2+ + 2e - Zn(s) -0.76 Comparing the calculated values to the actual standard reduction values, the values were fairly close. Some slight error can be seen in a few of the values, but otherwise they agreed with the actual values. Positive values correspond to spontaneous reactions (when the ion prefers to be reduced), whereas negative values correspond to non-spontaneous reactions (when the ion prefers to be oxidized). In part two of the experiment, it was predicted that aluminum would dissolve in a
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Experiment #4 - Discussion: In this experiment the...

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