Chemistry Electrode potentials question

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SUMMARY

The discussion centers on the calculation of electrode potentials in electrochemistry, specifically using the Nernst equation. The potential at an electrode is initially given by E = E° - (R * T / F) * log_e(Q_surface), where E° is the standard electrode potential and Q_surface is the reaction quotient at the electrode surface. Once equilibrium is reached, the potential stabilizes to E_eq = E° - (R * T / F) * log_e(K). The conversation also clarifies that if a constant reaction quotient Q_constant is maintained, the potential is E_constant = E° - (R * T / F) * log_e(Q_constant). Additionally, it is confirmed that a second electrode is necessary solely for measuring the potential difference, expressed as E_cell = E(Electrode 1) - E(Electrode 2).

PREREQUISITES
  • Understanding of the Nernst equation in electrochemistry
  • Familiarity with standard electrode potentials (E°)
  • Knowledge of reaction quotients (Q) and equilibrium constants (K)
  • Basic concepts of electrochemical cells and potential measurement
NEXT STEPS
  • Study the Nernst equation in detail and its applications in electrochemistry
  • Learn about the role of the Faraday constant (F) in electrochemical calculations
  • Explore the concept of equilibrium in electrochemical systems
  • Research methods for measuring electrode potentials in laboratory settings
USEFUL FOR

Chemistry students, electrochemists, and researchers involved in electrochemical analysis and potential measurements will benefit from this discussion.

Big-Daddy
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Am I right to think that the potential established at an electrode immediately when placed in solution is given by

[tex]E = E° - R \cdot T \cdot log_e(Q_{surface})[/tex]

where the potential E of the electrode results from the standard electrode potential (E°) of the reaction and the reaction quotient Qsurface at the electrode surface.

Then, once equilibrium is reached (usually fairly quickly for potential determining equilibria), we get a steady value of potential established, which is given by

[tex]E_{eq} = E° - R \cdot T \cdot log_e(K)[/tex]

Noting also that, once equilibrium conditions are established, the value of activities or concentrations at the electrode surface will be the same as their values in the bulk solution.

If the conditions of the system are held constant at a certain reaction quotient Qconstant instead of allowed to go to equilibrium, then the potential established is always

[tex]E_{constant} = E° - R \cdot T \cdot log_e(Q_{constant})[/tex]

Is this a correct understanding? And if this potential will be established on its own, is it correct to say that the only need for another electrode to join the first one is so that the difference in potentials can be measured (i.e. Ecell=E(Electrode 1)-E(Electrode 2))?
 
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Small modification to all my equations above. Instead of

[tex]- R \cdot T[/tex]

I should have

[tex]- \frac{R \cdot T}{F}[/tex]

Where F is the Faraday constant.
 

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