Galvanic cell

Definition

A galvanic cell is an electrochemical cell that converts chemical energy into electrical energy through spontaneous redox reactions. It consists of two half-cells, each containing an electrode and an electrolyte, where oxidation occurs at the anode and reduction occurs at the cathode. This process generates a flow of electrons through an external circuit, providing electric power.

5 Must Know Facts For Your Next Test

1. In a galvanic cell, the two half-cells are connected by a salt bridge that allows the movement of ions while preventing the mixing of different solutions.
2. The overall reaction in a galvanic cell can be described by the equation $$E_{cell} = E_{cathode} - E_{anode}$$, which shows the relationship between the standard electrode potentials.
3. Galvanic cells are often used in batteries, providing practical applications for energy storage and conversion.
4. The flow of electrons from the anode to the cathode generates an electric current, which can be harnessed to power electrical devices.
5. The efficiency of a galvanic cell can be influenced by factors such as temperature, concentration of reactants, and surface area of electrodes.

Review Questions

• What are the roles of the anode and cathode in a galvanic cell, and how do they contribute to the overall function of the cell?
  • In a galvanic cell, the anode is where oxidation occurs, leading to the release of electrons. Conversely, at the cathode, reduction takes place as it gains those electrons. Together, these processes create a flow of electrons through an external circuit, generating electric power. This interaction between the two electrodes is essential for transforming chemical energy into electrical energy.
• How does the presence of a salt bridge enhance the functionality of a galvanic cell?
  • The salt bridge in a galvanic cell serves as a crucial component by allowing ions to flow between the two half-cells while keeping their solutions separate. This ion transfer maintains charge neutrality within each half-cell, preventing the buildup of excess charge that could halt the reaction. Without a salt bridge, the electron flow would stop quickly due to charge imbalances, effectively rendering the cell non-functional.
• Evaluate how changes in temperature and concentration affect the performance and efficiency of galvanic cells.
  • Changes in temperature can increase or decrease reaction rates within a galvanic cell, impacting its voltage output and overall efficiency. Higher temperatures typically enhance reaction kinetics, potentially improving performance but also may lead to increased internal resistance. Concentration changes affect the Nernst equation; higher concentrations of reactants at either electrode can lead to greater potential differences and improved current output. Conversely, if products accumulate or reactant concentrations drop too low, it can diminish cell efficiency and power generation.

Related terms

anode: The electrode in a galvanic cell where oxidation occurs, resulting in the loss of electrons.

cathode:

The electrode in a galvanic cell where reduction takes place, leading to the gain of electrons.

electrolyte: A conductive solution or medium that allows ions to move between the anode and cathode in a galvanic cell.