Cell potential, also known as electrochemical potential or redox potential, is a measure of the driving force or tendency for a chemical reaction to occur in an electrochemical cell. It represents the potential difference between the two electrodes in a galvanic cell, which determines the spontaneity and direction of the redox reaction.
congrats on reading the definition of Cell Potential. now let's actually learn it.
The cell potential is the difference between the reduction potentials of the two half-reactions occurring at the anode and cathode in an electrochemical cell.
A positive cell potential indicates a spontaneous redox reaction, while a negative cell potential indicates a non-spontaneous reaction.
The magnitude of the cell potential determines the maximum amount of electrical work that can be obtained from the cell.
The cell potential is used to predict the direction and extent of a redox reaction, as well as to calculate the free energy change and equilibrium constant.
Cell potentials are important in the design and operation of batteries, fuel cells, and other electrochemical devices.
Review Questions
Explain how the cell potential is related to the electrode and reduction potentials of the half-reactions in an electrochemical cell.
The cell potential, $E_{cell}$, is the difference between the reduction potentials of the two half-reactions occurring at the cathode and anode in an electrochemical cell. Specifically, $E_{cell} = E_{cathode} - E_{anode}$. The reduction potential of the cathode half-reaction represents the tendency for reduction to occur, while the reduction potential of the anode half-reaction represents the tendency for oxidation to occur. The difference in these potentials drives the spontaneous redox reaction in the cell, with the magnitude of $E_{cell}$ determining the maximum electrical work that can be obtained.
Describe how the cell potential, free energy change, and equilibrium constant are related in an electrochemical system.
The cell potential, $E_{cell}$, is directly related to the Gibbs free energy change, $ riangle G$, and the equilibrium constant, $K_{eq}$, of the redox reaction occurring in an electrochemical cell. Specifically, the relationship is given by the equations: $ riangle G = -nFE_{cell}$ and $K_{eq} = e^{- riangle G/RT}$, where $n$ is the number of electrons transferred, $F$ is Faraday's constant, $R$ is the gas constant, and $T$ is the absolute temperature. A positive $E_{cell}$ indicates a spontaneous reaction with a negative $ riangle G$ and $K_{eq} > 1$, while a negative $E_{cell}$ indicates a non-spontaneous reaction with a positive $ riangle G$ and $K_{eq} < 1$. These relationships are crucial for predicting the feasibility and direction of electrochemical processes.
Explain the importance of cell potential in the design and operation of batteries, fuel cells, and other electrochemical devices.
The cell potential is a fundamental parameter in the design and operation of electrochemical devices such as batteries, fuel cells, and electrochemical sensors. The cell potential determines the voltage output of a battery or fuel cell, which is a critical factor in their energy density and power output. Additionally, the cell potential is used to predict the spontaneity and extent of the redox reactions occurring in these devices, allowing for the optimization of their performance and efficiency. Furthermore, the cell potential is a key parameter in electroanalytical techniques, where it is used to control and monitor electrochemical processes for applications in areas like energy storage, chemical analysis, and environmental monitoring.
The potential difference between a half-cell and the standard hydrogen electrode under standard conditions (25°C, 1 atm pressure, and 1 M concentrations).
An equation that relates the reduction potential of a half-cell to the standard reduction potential, temperature, and the activities of the reactants and products.