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Exercise 1: Construction of a Galvanic Cell Data Table 1. Spontaneous Reaction O

ID: 878593 • Letter: E

Question

Exercise 1: Construction of a Galvanic Cell

Data Table 1. Spontaneous Reaction Observations.

Metal in Solution

Observations

Zinc in Copper Sulfate

Zinc turns black

Copper in Zinc Sulfate

No change occured

Data Table 2. Voltmeter Readings.

Time (minutes)

Voltmeter Reading (Volts)

0

1.07

15

1.08

30

1.08

45

1.08

60

1.08

75

1.08

90

1.08

105

1.08

120

1.05

135

1.04

Data Table 3. Standard Cell Potential.

Equation

E°(Volts)

Oxidation Half-Reaction

Reduction Half-Reaction

Redox Reaction

Data Table 4. Galvanic Cell Setup.

Photograph of galvanic cell

Questions

What were the concentrations of the solutions (zinc solution, copper solution, and salt bridge)? Were the concentrations consistent with those of standard state conditions? Explain your answer.

Was the amount of electric energy produced in your galvanic cell consistent with the standard cell potential of the reaction (as calculated in Data Table 3)? Hypothesize why it was or was not consistent.

Was there evidence of electron transfer from the anode to the cathode? Use your data in Data Table 2 to explain your answer.

For the following redox reaction in a galvanic cell, write the oxidation half-reaction and the reduction-half reaction, and calculate the standard cell potential of the reaction. Use Table 1 in the Background as needed. Explain how you identified which half-reaction is the oxidizer and which is the reducer. Show all of your work.

Metal in Solution

Observations

Zinc in Copper Sulfate

Zinc turns black

Copper in Zinc Sulfate

No change occured

Explanation / Answer

Table 1. zinc is more reactive and displaces the copper in a redox reaction in which the zinc is oxidised and the copper is reduced but copper doesn't displace zinc because copper is less reactive.

In the first reaction, Zn(s) displaces Cu from CuSO4(Aq) and forms ZnSO4(aq) and Cu(s) which is black in color.

In the second reaction, Cu is less reactive then Zn and would not displace Zn from ZnSO4, thus no change was observed.

Table 3.

Oxidation half cell : Zn(s) ------> Zn2+(aq) + 2e- [Eo(reduction) = -0.76 V]

Reduction half cell : Cu2+(aq) + 2e- -------> Cu(s) [Eo(reduction) = 0.13 V]

Redox reaction : Zn(s) + CuSO4(aq) -----------> ZnSO4(aq) + Cu(s) [Eo = 0.89 V]

Table 4. Cell diagram,

Zn(s) | Zn2+(aq) || Cu2+(aq) | Cu(s)

The concentration of all are 1M and are consistent with those of standard state conditions