Messung des galvanischen Zellpotenzials

Messung der EMK verschiedener Halbzellkombinationen

Electrochemistry Advanced (University) 60 Min. ~$25,00

Ziel

Die elektromotorische Kraft (EMK) mehrerer Galvanzellen-Kombinationen messen und mit Standardreduktionspotenzialwerten vergleichen.

Hintergrund

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.

Sicherheitswarnungen

  • 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

Erforderliche PSA

goggles gloves lab_coat

Materialien

  • 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

Ausrüstung

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

Durchführung

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.

Erwartete Ergebnisse

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.

Aufräumen

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

Details

Kategorie
Electrochemistry
Schwierigkeit
Advanced (University)
Dauer
60 Min.
Geschätzte Kosten
$25,00
Schritte
8
Materialien
6

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Frequently Asked Questions

What is the objective of Messung des galvanischen Zellpotenzials?
Die elektromotorische Kraft (EMK) mehrerer Galvanzellen-Kombinationen messen und mit Standardreduktionspotenzialwerten vergleichen.
How difficult is Messung des galvanischen Zellpotenzials?
This experiment is rated as Advanced (University). It takes approximately 60 minutes to complete.
What safety precautions are needed for Messung des galvanischen Zellpotenzials?
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 Messung des galvanischen Zellpotenzials?
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 Messung des galvanischen Zellpotenzials?
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.