SCH4C
Name:_____________________
Partner’s Name:____________
Date of Lab: ________________
Date due:__________________
Galvanic Cell Lab
Purpose
The purpose of this lab is to determine how changing the half cell in a galvanic cell affects the cell potential
(voltage).
Materials
safety glasses
5 x 30 mL beakers
1x 250mL beaker
U tube
labels/wax pencil
glass wool
2 wires with alligator clips
voltmeter
LED clock/calculator/display
0.1 mol/L CuSO4
0.1 mol/L Zn(NO3)2
0.1 mol/L Ni(NO3)2
0.1 mol/L Fe(NO3)2
0.1 mol/L Mg(NO3)2
1 mol/L KNO3 for salt bridge
Figure 1: Galvanic Cell
Figure 2: Connecting the Galvanic Cell to a calculator.
Cu electrode
Zn electrode
Ni electrode
Fe electrode
Mg electrode
pennies
sand paper/ steel wool
SCH4C
Name:_____________________
Partner’s Name:____________
Date of Lab: ________________
Date due:__________________
Procedure
Build the Galvanic Cells and Determine Cell Potentials
1. Sand the surfaces on one end of each electrode until it is shiny.
2. Fill each 30mL beaker with a different metal ion solution and label them.
3. Fill U tube salt bridge with 1 mol/L KNO3 and stuff some glass wool in each end.
4. Set up your each cell as shown in the picture.
5. If the needle on your voltmeter swings the wrong way, switch the way the wires are attached.
6. Record the cell potential in Table 1.
7. Try to power a clock or calculator with a LCD screen by removing the battery and connecting it to your cell.
8. Record your observations in Table 1.
9. Repeat for the other cells.
10. Take the electrodes out of solution, rinse them with water and dry them with a paper towel. Do any of the
electrodes look different where they were submerged in solution? Record your observations in Table 2.
Observations
Table 1: Voltages and LCD test results for Galvanic Cells (6 marks, C)
Cell
1
2
3
4
5
6
Cell
Potential (V)
Did the
Clock/Calculator
Work With this
Cell? (Y/N)
Cu/Zn
Cu/Ni
Cu/Fe
Cu/Mg
Mg/Zn
Mg/Fe
NOTE: In this situation, iron is more likely to form Fe +2(aq) than Fe+3(aq)
Table 2: Physical description of the electrode after being connected to the galvanic cell
Electrode Dry Electrode After Reaction
Cu
Zn
Ni
Fe
Mg
SCH4C
Name:_____________________
Partner’s Name:____________
Date of Lab: ________________
Date due:__________________
Questions
1. Will the cells that contain copper work if you use a penny instead of a Cu electrode? Try it!
2.
What happens if you remove the voltmeter?
3.
What happens if you remove the salt bridge?
4.
a) In a galvanic cell, the metal higher on the activity series is always oxidized and the metal lower on the activity
series is reduced. Oxidation occurs at the anode and reduction occurs at the cathode. Using this information,
identify the anode and the cathode for each cell in Table 1. (6 marks, I)
b) Which metal was the anode of the cell most often? (1 mark, I)
c) Which metal was the cathode of the cell most often? (1 mark, I)
d) Which cell had the largest cell potential (voltage)? (1 mark, I)
e) Which cell had the smallest cell potential? (1 mark,I)
e) Cu is lowest on the activity series. For the cells with Cu and another metal, what happed to the cell potential as
the reactivity of the other metal increased (higher on activity series)? (2 marks, I)
f) Mg is highest on the activity series. For the cells with Mg and another metal, what happened the cell potential
as the reactivity of the other metal increased (higher on activity series)? (2 marks,I)
g) What happened when you tried to use the penny as an electrode? Was the voltage the same as with the Cu
strip? ( 1 mark, C)
5.
For the galvanic cell with the highest voltage:
a)
Write the anode, cathode, and overall cell reactions that occur. (4 marks, I)
SCH4C
Name:_____________________
Partner’s Name:____________
Date of Lab: ________________
Date due:__________________
b)
c)
d)
e)
Draw a LARGE diagram of your galvanic cell (2 marks,C)
Label the two electrodes, two solutions, anode, cathode, voltmeter and salt bridge (4 marks, C)
Show where reduction and oxidation occur ( 1mark,C)
Show the direction of electron flow in the wire and the direction of ion flow. (1 mark,C)
f) Predict which electrode increases in mass and which electrode decreases in mass. Justify your predictions.
(3 marks, I)
g) Use your solubility table and explain why KNO3 makes a better a salt bridge for this lab instead of K3PO4.
(3 marks, C)
6.
About how much voltage does it take to power the LCD? Explain how you know. (2 mark, I)