Pre-lab Questions:
1. Define cathode and anode.
The cathode is the negative electrode where electrons enter a cell.
The anode is the positive electrode where electrons leave a cell.
Electron flow determines which electrode is the cathode and which is the anode.
2. What are considered standard conditions for reduction potentials?
Reduction potentials are measured at a temperature of 25°C or 298 K.
They are reported at a pressure of 1 atmosphere or 101.325 kPa.
Solutions are 1 molar (1 M) in concentration.
These conditions are arbitrarily set as the "standard" or reference conditions.
Reduction potentials measured under these standard conditions are called standard
reduction potentials (E° values).
3. What is the standard emf/cell voltage for a galvanic cell of: 2.01
3Cu2+ (����)+ 2Al (��) ⟶ 2Al3+ (����) + 3Cu (��)
Ni(��) │Ni 2+ (����)║Ag+(����) │Ag( ��)
4. Identify each element in the pair as a likely cathode or anode.
a) Ag and H Silver (Ag) cathode, Hydrogen (H) anode
b) Fe and Al Iron (Fe) cathode, Aluminum (Al) anode
c) Cu and Zn Copper (Cu) cathode, Zinc (Zn) anode
, Report Form (All Parts):
Solu琀椀on # [Zn2+] [Cu2+] E Calculated E Experimental
(Theore琀椀cal)
1 1M 1M 1.11
2 1M 0.5M 1.09
3 1M 0.25M 1.074
4 1M 0.125M 1.066
5 1M 0.0625M 1.057
6 1M 0.0312M 1.054
7
8
9
10
Show Calculations (if using Excel, attach printout of spreadsheet and graph)
Additional Questions:
1. What do you notice about the relationship between cell potential (E) and concentration of the
cathode solution, particularly as compared to standard conditions? The relationship
between cell potential (E) and the concentration of the cathode solution is
described by the Nernst equation, which shows that the cell potential varies
logarithmically with the concentration of the cathode solution, and deviates
from the standard conditions as the concentration changes.
2. How do you think this would change if the cathode was held constant while the anode was
varied? If the cathode is held constant while the anode is varied, the
resulting current will still depend on the potential difference between the
anode and cathode, but the details of the electrochemical reaction at the
anode will be different.
3. If you were to repeat this experiment again, but increase the concentrations of the copper
solution instead, what effect would you observe in the E value of the cells? Increasing
the concentration of the copper solution in the cell would increase the E
value of the cell, according to the Nernst equation, which shows that the
cell potential increases logarithmically with the concentration of the
1. Define cathode and anode.
The cathode is the negative electrode where electrons enter a cell.
The anode is the positive electrode where electrons leave a cell.
Electron flow determines which electrode is the cathode and which is the anode.
2. What are considered standard conditions for reduction potentials?
Reduction potentials are measured at a temperature of 25°C or 298 K.
They are reported at a pressure of 1 atmosphere or 101.325 kPa.
Solutions are 1 molar (1 M) in concentration.
These conditions are arbitrarily set as the "standard" or reference conditions.
Reduction potentials measured under these standard conditions are called standard
reduction potentials (E° values).
3. What is the standard emf/cell voltage for a galvanic cell of: 2.01
3Cu2+ (����)+ 2Al (��) ⟶ 2Al3+ (����) + 3Cu (��)
Ni(��) │Ni 2+ (����)║Ag+(����) │Ag( ��)
4. Identify each element in the pair as a likely cathode or anode.
a) Ag and H Silver (Ag) cathode, Hydrogen (H) anode
b) Fe and Al Iron (Fe) cathode, Aluminum (Al) anode
c) Cu and Zn Copper (Cu) cathode, Zinc (Zn) anode
, Report Form (All Parts):
Solu琀椀on # [Zn2+] [Cu2+] E Calculated E Experimental
(Theore琀椀cal)
1 1M 1M 1.11
2 1M 0.5M 1.09
3 1M 0.25M 1.074
4 1M 0.125M 1.066
5 1M 0.0625M 1.057
6 1M 0.0312M 1.054
7
8
9
10
Show Calculations (if using Excel, attach printout of spreadsheet and graph)
Additional Questions:
1. What do you notice about the relationship between cell potential (E) and concentration of the
cathode solution, particularly as compared to standard conditions? The relationship
between cell potential (E) and the concentration of the cathode solution is
described by the Nernst equation, which shows that the cell potential varies
logarithmically with the concentration of the cathode solution, and deviates
from the standard conditions as the concentration changes.
2. How do you think this would change if the cathode was held constant while the anode was
varied? If the cathode is held constant while the anode is varied, the
resulting current will still depend on the potential difference between the
anode and cathode, but the details of the electrochemical reaction at the
anode will be different.
3. If you were to repeat this experiment again, but increase the concentrations of the copper
solution instead, what effect would you observe in the E value of the cells? Increasing
the concentration of the copper solution in the cell would increase the E
value of the cell, according to the Nernst equation, which shows that the
cell potential increases logarithmically with the concentration of the
