23.2 Cell Potentials
23.2 Cell Potentials
Lesson Objectives
- Describe how an electrical potential is generated in an electrochemical cell.
- Describe the standard hydrogen electrode and how it is used to determine the standard cell potentials of other
half-cells. - Calculate the standard cell potentials from a table of standard reduction potentials.
- Predict the behavior of oxidizing and reducing agents based on their position in the table of standard reduction
potentials.
Lesson Vocabulary
- cell potential
- electrical potential
- reduction potential
- standard cell potential
- standard hydrogen electrode
Check Your Understanding
Recalling Prior Knowledge
- What are the parts of an electrochemical cell and how does it work?
- What is the difference between a spontaneous and a nonspontaneous reaction?
Voltaic cells harness energy from spontaneous redox reactions to produce electrical energy. However, not all redox
reactions have the same ability to generate an electric current. In this lesson, you will learn about electrical potential
and how to determine the potential of various electrochemical cells.
Reduction Potential
Electrical potentialisa measurement of the ability of a voltaic cell to produce an electric current. Electrical
potential is typically measured in volts (V). Like energy, electrical potential is a relative term; it can only be measured
by comparison with something else. The voltage that is produced by a given voltaic cell is the difference in electrical
potential between the two half-cells, but it is not possible to measure the electrical potential of an isolated half-
cell. For example, if only a zinc half-cell were constructed, no complete redox reaction can occur, so no electrical