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Galvanic Cells

Electrochemical cells in which a thermodynamically favored redox reaction takes place are called galvanic cells.

Example

Example

  • A galvanic cell based on the spontaneous reaction between copper and silver(I) is depicted in the image above and repeated on the next slide.
  • The cell is comprised of two half-cells, each containing the redox conjugate pair (“couple”) of a single reactant.
    • The half-cell shown at the left contains the Cu(0)/Cu(II) couple in the form of a solid copper foil and an aqueous solution of copper nitrate.
    • The right half-cell contains the Ag(I)/Ag(0) couple as solid silver foil and an aqueous silver nitrate solution.
Diagram
Components of galvanic cells

Components of galvanic cells

  • The anode of an electrochemical cell is the electrode at which oxidation occurs (in this case, the Cu foil).
  • The cathode is the electrode where reduction occurs (the Ag foil).
  • The redox reactions in a galvanic cell occur only at the interface between each half-cell’s reaction mixture and its electrode.
    • To keep the reactants separate while maintaining charge-balance, the two half-cell solutions are connected by a tube filled with inert electrolyte solution called a salt bridge.
Reaction

Reaction

  • The thermodynamically favorable reaction in this cell:
    • Produces Cu2+ cations in the anode half-cell.
    • Consumes Ag+ ions in the cathode half-cell.
  • This results in a compensatory flow of inert ions from the salt bridge that maintains charge balance.
  • Increasing concentrations of Cu2+ in the anode half-cell are balanced by an influx of NO3− from the salt bridge.
  • A flow of Na+ into the cathode half-cell compensates for the decreasing Ag+ concentration.
Jump to other topics
1

Structure - Models of the Particulate of Matter

2

Structure - Models of Bonding & Structure

3

Structure - Classification of Matter

3.1

The Periodic Table: Classification of Elements

3.2

Periodic Trends

3.3

Group 1 Alkali Metals

3.4

Halogens

3.5

Noble gases, group 18

3.6

Functional Groups: Classification of Organic

3.7

Functional Group Chemistry

3.8

Alkanes

3.9

Alcohols

3.10

Halogenoalkanes

4

Reactivity - What Drives Chemical Reaction?

5

Reactivity - How Much, How Fast & How Far?

6

Reactivity - The Mechanisms of Chemical Change

7

Measurement, Data Processing & Analysis

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