Nernst Equation and Electrode Potentials Quiz

Study Notes

Cell Potential and Equations

The Nernst equation relates the cell potential (E) to the standard potential (E°) and the activities (or concentrations) of the electroactive species.
The equation is expressed as ( E = E° - \frac{RT}{nF} \ln Q ), where Q is the reaction quotient, R is the universal gas constant, T is the temperature in Kelvin, n is the number of moles of electrons transferred, and F is Faraday's constant.

Condition for Cell Potential

The cell potential equals the standard potential (E°) when the activities of the electroactive species are at standard conditions (1 M concentration, 1 atm pressure, and at a specified temperature).

Common Form of the Nernst Equation

The Nernst equation is typically written in the form ( E = E° - \frac{0.0592}{n} \log Q ).
This common form is applicable at standard temperature, which is 25 degrees Celsius (298 K).

Equilibrium Constant

For the reversible reaction ( \text{Zn(s)} + \text{Cu}^{2+}(aq) \rightleftharpoons \text{Zn}^{2+}(aq) + \text{Cu(s)} ), the equilibrium constant (K) under standard conditions is given by ( K = \frac{[\text{Zn}^{2+}]}{[\text{Cu}^{2+}]} ).

Concentration Changes

As the reaction progresses toward equilibrium, the concentration of ( \text{Cu}^{2+} ) decreases while the concentration of ( \text{Zn}^{2+} ) increases.

Description

Test your knowledge of the Nernst equation and its application in determining cell potential and electrode potentials at non-standard conditions. Explore the relationship between standard potential, activities of electroactive species, and temperature.