3B Scientific Electrochemistry Kit - Manual (Page 8)

9
Experiment 1 - Measuring voltage Student instructions
Measuring the voltage of galvanic cells
Chemicals Hazard
symbols
R phrases S phrases Equipment
Copper (II)-sulfate-(5 H
2
O) 22-36/38-50/53 22-60-61 Meter
Zinc sulfate-(7H
2
O) 36/38-50/53 22-25-60-61 Electrodes:
1 Cu, 1 Zn,1 Ag, 1 Fe, 1 Ni
Silver nitrate 34-50/53 26-45-60-61 2 Experiment cables
Iron (II)-sulfate-(7 H
2
O) 22-36/38 24/25 2 Pipettes
Nickel sulfate-(6H
2
O) 22-40-42/43-
50/53
22-36/37-60-
61
Distilled water
--- ---
Warning: Please take care: Salts of heavy metals are poisonous!
Experiment procedure:
1. The prepared 1.0 and 0.1 molar electrolyte solutions should be given to the students. Students require no more than
10 ml of the relevant solution each.
2. Assemble the battery block as described.
3. Fill the chambers with electrolyte using the pipette (included in the case) and insert the appropriate electrodes.
Clean the pipette thoroughly before using it add the next electrolyte.
4. After the chambers (at least 2, at most 8) have been prepared for the experiment as described, start measuring
voltages.
In this experiment, each of 5 chambers is filled with a separate electrolyte and
the relevant electrodes are added to form a galvanic cell
Cu / CuSO
4
, Zn / ZnSO
4
, Ag / AgNO
3
, Fe / FeSO
4
, Ni / NiSO
4
5. To measure voltage, two experiment cables (red/blue with 2mm plugs - included in case) should be connected to the
voltmeter. The connection between the two electrodes and the meter is made by means of crocodile clips.
6. The voltage produced by the galvanic cell can be read off the meter. If a negative voltage is displayed, reverse the
polarity of the two electrodes.
Observation and evaluation:
Enter the results of the experiment in the following table and evaluate them.
Galvanic cell Voltage (V)
Electrolyte 1.0 mol/l
Voltage (V)
Electrolyte 0.1 mol/l
Cu / Zn
Cu / Ag
Cu / Fe
Cu / Ni
Zn / Ag
Zn / Fe
Zn / Ni
Fe / Ag
Fe / Ni
Ag / Ni