Galvanic cells
Cells that convert chemical energy into electrical energy through spontaneous redox reactions.
What is Galvanic cells?
An electrochemical cell that converts chemical energy from spontaneous redox reactions into electrical energy.
Key formula / rule: Standard Cell Potential
Key points
- Define a galvanic cell and its function.
- Identify the anode and cathode in a galvanic cell.
- Explain the role of the salt bridge.
- Describe the flow of electrons and ions.
Common exam trap
Confusing anode and cathode terminals (especially their polarity in galvanic vs. electrolytic cells).
Definitions
- Term
Galvanic Cell
- Meaning
An electrochemical cell that converts chemical energy from spontaneous redox reactions into electrical energy.
- Term
Anode
- Meaning
The electrode where oxidation occurs. In a galvanic cell, it is the negative terminal.
- Term
Cathode
- Meaning
The electrode where reduction occurs. In a galvanic cell, it is the positive terminal.
- Term
Salt Bridge
- Meaning
A U-shaped tube containing an electrolyte (e.g., KNO3, NH4Cl) that connects the two half-cells of a galvanic cell, allowing ion migration to maintain electrical neutrality.
- Term
Cell Potential (Ecell)
- Meaning
The potential difference between the two electrodes of an electrochemical cell, which drives the flow of electrons.
- Term
Standard Electrode Potential (E°)
- Meaning
The potential of an electrode measured under standard conditions (298 K, 1 atm pressure, 1 M concentration).
Learning objectives
Define a galvanic cell and its function.
Identify the anode and cathode in a galvanic cell.
Explain the role of the salt bridge.
Describe the flow of electrons and ions.
Calculate cell potential under standard and non-standard conditions.
Predict the spontaneity of a redox reaction using cell potential.
Formulae
- Name
Standard Cell Potential
- Note
Calculated using standard electrode potentials at 298 K and 1 atm.
- Expression
E°cell = E°cathode - E°anode
- Name
Cell Potential (Nernst Equation)
- Note
Relates cell potential to non-standard conditions of temperature, pressure, and concentration. R=gas constant, T=temperature, n=moles of electrons, F=Faraday's constant, Q=reaction quotient.
- Expression
Ecell = E°cell - (RT/nF)lnQ
- Name
Cell Potential (Nernst Equation at 298K)
- Note
Simplified form of Nernst equation at standard temperature (298 K).
- Expression
Ecell = E°cell - (0.0592/n)logQ
Prerequisites
Understanding of redox reactions (oxidation and reduction).
Basic concepts of electrochemistry.
Knowledge of ions and electrolytes.
Familiarity with standard electrode potentials.
Common mistakes
Confusing anode and cathode terminals (especially their polarity in galvanic vs. electrolytic cells).
Incorrectly identifying the species being oxidized or reduced.
Forgetting the role of the salt bridge in maintaining electrical neutrality.
Assuming all redox reactions are spontaneous without checking the cell potential.
Errors in applying the Nernst equation.
Keywords
Galvanic Cell
Voltaic Cell
Redox Reaction
Electrochemistry
Anode
Cathode
Salt Bridge
Cell Potential
Electrode Potential
Nernst Equation
Spontaneity
Practice preview
Which of the following statements correctly describes a galvanic cell?…
easy
In a galvanic cell, the anode is the electrode where:…
easy
The standard electrode potential of a cell is calculated using the formula:…
easy