Voltaic Cell Potential Measurement

Measuring EMF of various half-cell combinations

Electrochemistry Advanced (University) 60 min ~$25.00

Objective

Measure the electromotive force (EMF) of multiple galvanic cell combinations and compare with standard reduction potential values.

Background

By constructing galvanic cells with different metal/metal-ion half-cell combinations and measuring their voltages, students can experimentally determine relative electrode potentials. Comparing measured values with standard reduction potentials validates electrochemical theory.

Safety Warnings

  • Lead compounds are toxic — handle with extreme care
  • Wear nitrile gloves throughout
  • Wash hands immediately if lead solution contacts skin
  • Dispose of lead waste in designated containers

Required PPE

goggles gloves lab_coat

Materials

  • Zinc strip and 1M ZnSO₄ (100 mL)
  • Copper strip and 1M CuSO₄ (100 mL)
  • Lead strip and 1M Pb(NO₃)₂ (100 mL)
    Toxic
  • Tin strip and 1M SnCl₂ (100 mL)
  • KNO₃ salt bridge solution (200 mL)
    Saturated
  • Filter paper strips (10)
    For salt bridges

Equipment

Six 250 mL beakers High-impedance voltmeter or multimeter Wires with alligator clips Sandpaper

Procedure

1

Sand all metal strips until shiny. Prepare 1M solutions of each metal salt in separate beakers.

5 min Wear gloves for lead compounds
2

Prepare salt bridges by soaking filter paper strips in saturated KNO₃ solution.

3 min
3

Construct a Zn/Cu cell: connect with a salt bridge and measure the EMF with the voltmeter.

5 min
4

Construct a Zn/Pb cell and measure EMF.

5 min Handle lead carefully
5

Construct a Zn/Sn cell and measure EMF.

5 min
6

Construct a Cu/Pb cell and measure EMF.

5 min
7

Construct a Sn/Cu cell and measure EMF.

5 min
8

Tabulate all results. Calculate theoretical EMF values using standard reduction potentials and compare with measured values.

15 min

Expected Results

Zn/Cu: ~1.10 V, Zn/Pb: ~0.63 V, Zn/Sn: ~0.62 V, Cu/Pb: ~0.47 V, Sn/Cu: ~0.48 V. Measured values should be within 0.05-0.15 V of theoretical due to non-standard conditions.

Cleanup

Collect all lead-containing waste in designated containers. Dispose of copper waste separately. Rinse metal strips and store. Wash hands thoroughly.

Details

Category
Electrochemistry
Difficulty
Advanced (University)
Duration
60 min
Est. Cost
$25.00
Steps
8
Materials
6

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Frequently Asked Questions

What is the objective of Voltaic Cell Potential Measurement?
Measure the electromotive force (EMF) of multiple galvanic cell combinations and compare with standard reduction potential values.
How difficult is Voltaic Cell Potential Measurement?
This experiment is rated as Advanced (University). It takes approximately 60 minutes to complete.
What safety precautions are needed for Voltaic Cell Potential Measurement?
Key safety precautions include: Lead compounds are toxic — handle with extreme care; Wear nitrile gloves throughout; Wash hands immediately if lead solution contacts skin.
What materials are needed for Voltaic Cell Potential Measurement?
The main materials required are: Zinc strip and 1M ZnSO₄, Copper strip and 1M CuSO₄, Lead strip and 1M Pb(NO₃)₂, Tin strip and 1M SnCl₂, KNO₃ salt bridge solution.
What results should I expect from Voltaic Cell Potential Measurement?
Zn/Cu: ~1.10 V, Zn/Pb: ~0.63 V, Zn/Sn: ~0.62 V, Cu/Pb: ~0.47 V, Sn/Cu: ~0.48 V. Measured values should be within 0.05-0.15 V of theoretical due to non-standard conditions.