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Electrochemistry- Cathodes and Anodes

(there are six procedures with the same questions for each procedure)

Procedure 1 LAB:

Beaker #1: 150 ml CuSO4
Beaker #2: 150 ml SnCl2
Salt Bridge connects the two beakers
electrode in CuSO4 is set to copper
electrode in SnCl2 is set to tin
volt meter reads .4761

Question:

1. Identify the cathode and anode in this system.

2. Use the table for Standard Reduction Potentials at 25 degrees C (half reaction table increasing strength as an oxidizing agent). How does teh calculated value compare to the experimentally obtained value?

3. What does the reduction potential of this cell say about the spontaneity of this redox reaction? Are products or reactants favored? How do you know?

Procedure 2 LAB:

Beaker #1 150 ml CuSO4
Beaker #2 150 ml AgNO3
Salt bridge connects the two
electrode for beaker #1 set to copper
electrode for beaker #2 set to silver
Volt meter reads -.4594

Questions

1. Identify the cathode and anode in this system.

2. Use the table for standard reduction potentials at 25 degrees C (half reaction table increasing strength as an oxidizing agent). How does the calculated value compare to the experimentally obtained value?

3. What does the reduction potential of this cell sy about the spontaneity of this redox reaction? Are products or reactants favored? How do you know?

LAB Procedure 3

Beaker #1 150 ml CuSO4
Beaker #2 150 ml ZnSO4
Salt Bridge
electrode CuSO4 set to copper
electrode ZnSO4 set to zinc
Volt meter reads 1.103

Questions

1. Identify the cathode and anode in this system.

2. Use table for standard reduction potentials at 25 degrees C (half reaction table increasing strength as an oxidizing agent). How does the calculated value compare to the experimentally obtained value?

3. What does the reduction potential of this cell say about the spontaneity of this redox reaction? Are products or reactants favored? How do you know?

Procedure 4 LAB

Beaker #1 150ml SnCl2
Beaker #2 150ml ZnSO4
Salt bridge
electrode SnCl2 set to tin
electrode ZnSO4 set to zinc
Volt meter reads .6269

Questions

1. Identify the cathode and anode in this system.

2. Use the table for standard reduction potentials at 25 degrees C (half reaction table increasing strength as an oxidizing agent). How does the calculated value compare to the experimentally obtained value?

3. What does the reduction potential of this cell say about the spontaneity of this redox reduction? Are products or reactants favored? How do you know?

Procedure 5 LAB

Beaker #1 150ml SnCl2
Beaker #2 150ml AgNO3
Salt Bridge
electrode SnCl2 set to tin
electrode AgNO3 set to silver
Volt meter reads -.9357

Questions

1. Identify the cathode and anode in this system.

2. Use the table for standard reduction potential at 25 degrees C (half reaction table increasing strength as an oxidizing agent). How does the calculated value compare to the experimentally obtained value?

3. What does the reduction potential of this cell say about the spontaneity of this redox reaction? Are the products or reactants favored? How do you know?

Procedure 6 LAB

Beaker #1 150ml ZnSO4
Beaker #2 150ml AgNO3
Salt bridge
electrode ZnSO4 set to zinc
electrode AgNO3 set to silver
Volt meter reads -1.562

Question

1. Identify the cathode and anode in this system.

2.Use the table for standard reduction potential at 25 degrees C (half reaction table increasing strength as an oxidizing agent). How does the calculated value compare to the experimentally obtained value?

3. What does the reduction potential of this cell say about the spontaneity of this redox reaction? Are products or reactants favored? How do you know?

Solution Preview

Lab 1
Look at your voltmeter reading to get an idea of which half reaction is oxidized and which is reduced.

1. Cathode (reduction): Copper
Anode (oxidation): Tin

2. From Standard Reductions Table in back of Chemistry book.
Cu2+ + 2e- -> Cu(s) E = 0.337 V
Sn(s) -> Sn2+ + 2e- E = 0.14 V

E(total) = 0.337 + 0.14 = 0.477 V

3. Spontaneity of a chemical reaction is determined by the overall cell potential Ecell. If Ecell>0, the reaction is spontaneous and if Ecell<0, the reaction will not be spontaneous. This can also be looked at in terms of the gibss free energy (G). If G<0, the reaction is spontaneous and if G>0, the reaction will not ...

Solution Summary

Cathodes and anodes in an electrochemical system are discussed. Redox reactions and the reduction of potential are found.

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