Demonstration of a Voltaic Cell

Voltaic cells used in research consist of two half-cells, each with an electrode and an electrolyte, separated by a porous boundary. The purpose of this investigation is to demonstrate the design and operation of a voltaic cell used in scientific research.

Problem
What is the design and operation of a voltaic cell?

Design
Voltaic Cell Animation
Three different combinations of metals and metal ion electrolytes are used in the simulation of a voltaic cell.

Procedure

Download a student worksheet.

1. Set up the simulation to represent a voltaic cell with the following materials:

Anode Solution (1M) Cathode Solution (1M)
Ag AgNO3 Cu Cu(NO3)2
Cu Cu(NO3)2 Zn Zn(NO3)2
Ag AgNO3 Zn Zn(NO3)2

2. For each design, use the voltmeter to determine which electrode is positive and which is negative.
3. With the voltmeter connected, remove and then replace the various parts of the cell.
4. Record  the voltages produced for each cell combination. Potentials must be positive, if they are not the electrodes are reversed.

Observations

Flash applet created by the Chemical Education Research Group, Department of Chemistry, Iowa State University
 

Anode Solution (1M) Cathode Solution (1M) Cell Potential
Ag AgNO3 Cu Cu(NO3)2  
Cu Cu(NO3)2 Zn Zn(NO3)2  
Ag AgNO3 Zn Zn(NO3)2  

Analysis

1. Label the diagrams below to show the three identified voltaic cells.  Identify electrodes, electrolytes, electron flow and direction of ion movement.  Label the cathode, anode, and write the net cell reaction equations for each.

2. Indicate whether the following processes occur at the cathode or at the anode of a voltaic cell.

    a. reduction half-reaction _____________________________________

    b. oxidation half-reaction _____________________________________

    c. reaction of the strongest reducing agent ______________________

    d. reaction of the strongest oxidizing agent ______________________

3. Use the tool to design the voltaic cell with the greatest cell potential.
    Explain why you chose this combination.