http://www.ck12.org Chapter 23. Electrochemistry
23.2 Cell Potential
Lesson Objectives
- Diagram and explain the operation of a standard hydrogen cell.
- Explain how to determine standard reduction potentials.
- Use standard reduction potentials to calculate the total potential of a given electrochemical cell.
- Use the Nernst equation to calculate reduction potentials under non-standard conditions.
Lesson Vocabulary
- electrical potential: A measurement of the ability of a voltaic cell to produce an electric current; typically
measured in volts (V). - standard reduction potential: A measurement of the tendency of a given half-reaction to occur as a reduction
in an electrochemical cell. - cell potential: The difference in standard reduction potentials between the two half-cells in an electrochemical
cell. - standard cell potential: The potential of an electrochemical cell when the temperature is 25°C, all aqueous
components are present at a concentration of 1 M, and all gases are at the standard pressure of 1 atm. - standard hydrogen electrode (SHE): A reference half-cell that can be used with another electrode (half-cell)
to determine its standard reduction potential. - anode: The cell in which the oxidation takes place.
- cathode: The cell in which the reduction takes place.
Check Your Understanding
- How do you use the activity series to determine whether a given redox reaction will occur spontaneously?
Introduction
When designing electrochemical cells such as batteries, scientists and engineers must be able to calculate electrical
potentials in order to create powerful and sensible energy sources. By comparing and combining reduction reactions,
different cell potentials can be obtained and utilized to conduct an effective electric current. In this lesson you will
learn how to predict whether or not a redox reaction will occur spontaneously based on the electrical potentials of
various cells.