key term - 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 takes place at the cathode. The flow of electrons from the anode to the cathode generates an electric current that can be harnessed for various applications.

5 Must Know Facts For Your Next Test

1. Galvanic cells are also known as voltaic cells and are commonly used in batteries.
2. The standard electrode potential for each half-cell can be used to predict the overall cell voltage using the Nernst equation.
3. In a galvanic cell, the chemical reaction is spontaneous, meaning it occurs naturally without the need for external energy input.
4. The salt bridge or porous membrane is essential in maintaining electrical neutrality by allowing ion flow between the half-cells.
5. The total cell potential of a galvanic cell can be calculated by subtracting the reduction potential of the anode from that of the cathode.

Review Questions

• How do the functions of the anode and cathode contribute to the overall operation of a galvanic cell?
  • In a galvanic cell, the anode and cathode play crucial roles in facilitating redox reactions. The anode is where oxidation occurs, leading to the release of electrons into the external circuit. Meanwhile, at the cathode, reduction takes place as it accepts those electrons. This flow of electrons from the anode to the cathode generates an electric current, which is harnessed for practical use.
• Discuss how a salt bridge enhances the functionality of a galvanic cell and its importance in maintaining ion balance.
  • The salt bridge in a galvanic cell is critical for maintaining electrical neutrality by allowing ions to flow between the two half-cells. As oxidation at the anode generates positive ions and reduction at the cathode consumes them, the salt bridge helps balance these changes by allowing anions to move toward the anode and cations toward the cathode. This movement prevents charge buildup that could halt the reaction and ensures continuous electron flow, making the cell operational.
• Evaluate how changes in concentration of reactants in a galvanic cell impact its cell potential and overall efficiency.
  • Changes in reactant concentration within a galvanic cell directly affect its cell potential according to Le Chatelier's principle and can be quantitatively assessed using the Nernst equation. When reactant concentrations increase, it can lead to a higher driving force for the redox reactions, thus increasing cell potential. Conversely, if reactants are depleted, the cell potential decreases, affecting efficiency. Understanding this relationship allows for optimization of battery design and performance by controlling reactant concentrations.

Related terms

Anode:

The electrode in a galvanic cell where oxidation occurs, releasing electrons into the external circuit.

Cathode:

The electrode in a galvanic cell where reduction takes place, accepting electrons from the external circuit.

Electrolyte: A conductive solution or substance that allows ions to move between the electrodes in a galvanic cell, facilitating the redox reactions.