How to Read a Voltaic Cell Diagram

Zinc is one of the most common elements used in a voltaic cell diagram.

A voltaic cell is an example of an electrochemical cell, or a combination of a salt bride and electrodes that is used to generate an electric current. The type of reaction that generates the electric current is a redox reaction, which is a reaction that involves oxidation and reduction. An oxidation reaction involves the loss of electrons, whereas a reduction reaction involves the gain of electrons. The voltaic cell diagram illustrates this process. It is important to know how to read a voltaic cell diagram because it will help you to understand the mechanism of the redox reaction.

Things You'll Need

• Computer
• Chemistry book
• Periodic table
• Pen
• Paper

Instructions

1. Find the salt bridge. The salt bridge is at the center of the voltaic cell diagrams. It allows the ions to flow from the anode to the cathode. Often, this will be labeled by placing arrows in the direction of the cathode.

2. Locate the anode. The anode is where the oxidation reaction occurs. Most often, the metal placed in the beaker at this location is zinc.

3. Write the half reaction for the oxidation that occurs at the anode. In oxidation, electrons are part of the product of the reaction. For example, when zinc reduces, the half reaction is:

   Zn gives you Zn+2 + 2e-.

4. Locate the cathode. The cathode is where the reduction reaction occurs. The most common metal that is placed within the beaker at this location is copper.

5. Write the half reaction for the reduction reaction that occurs at the cathode. In a reduction reaction, the electrons are part of the reactants. For example, the half reaction for the reduction of copper is:

   Cu+2 + 2e- gives you Cu.

6. Examine which electrode is a solid color and which electrode is not colored in. The electrode that is not colored is the anode. As the redox reaction occurs, the anode decomposes. The electrode that is colored in, or a solid color, is the cathode. During the redox reaction, the deposition takes place on the metal that is gaining the electrons.

References

• Los Alamos National Laboratory: Periodic Table of Elements
• Clackamas Community College: Voltaic Cells
• Aus-e-Tute: Galvanic (Voltaic) Electrochemical Cells
• Hyperphysics: Voltaic Cells