Redox Reactions and the Galvanic Cell

A set of vocabulary flashcards covering the components, chemical potentials, and functions of galvanic cells and redox reactions based on the lecture notes.

Galvanic cell

An electrochemical power source that generates electric current through a redox reaction, constructed from two half-cells connected by a conductor and a salt bridge.

Anode

The electrode where oxidation occurs and the reductant reacts; it is the half-cell where electrons are released and has the lowest $E^0$ value.

Cathode

The electrode where reduction occurs and the oxidant reacts; it is the half-cell where electrons are accepted and has the highest $E^0$ value.

Daniell cell

A specific galvanic cell where the reactions involve Zinc ($ZnSO_4 \rightarrow Zn^{2+} + SO_4^{2-}$) and Copper ($CuSO_4 \rightarrow Cu^{2+} + SO_4^{2-}$).

$$E^0(Zn^{2+}/Zn)$$

$$-0.76\,V$$

$$E^0(Cu^{2+}/Cu)$$

$$0.34\,V$$

Salt bridge (or Electrolyte bridge)

A component that connects two half-cells to close the electrical circuit and compensate for change in charge by allowing ion migration.

Salt bridge ion migration

Anions of the electrolyte solution move toward the anode, while cations migrate toward the cathode.

Schematic representation of a Daniell cell

$Anode // cathode$ or specifically $Zn/Zn^{2+} // Cu^{2+}/Cu$

Source voltage ($U^0_b$) formula

Calculated as the difference in standard potentials: $U^0_b = \Delta E^0 = E^0_{ox} - E^0_{red}$

Source voltage ($U^0_b$) of a Daniell cell

$$0.34\,V - (-0.76\,V) = 1.10\,V$$

Battery

A number of galvanic cells connected in series to achieve a higher source voltage, such as Leclanché, Alkaline, or Lithium batteries.