Activity and electrochemical potential gradients
Research context
postgraduate concept · established · As of 2026-10-10
Species transport is driven by chemical and electrical contributions to electrochemical potential.
Key knowledge
Species transport is driven by chemical and electrical contributions to electrochemical potential. Replacing activity with concentration is justified only by the adopted activity model; in concentrated electrolytes, thermodynamic factors and cross-species constraints matter.
Values and equations
mu_tilde_i = mu_i0 + R*T*ln(a_i) + z_i*F*phi
- mu_tilde_i
- molar electrochemical potential J mol^-1
- mu_i0
- standard chemical potential J mol^-1
- R
- molar gas constant J mol^-1 K^-1
- T
- temperature K
- a_i
- dimensionless activity 1
- z_i
- signed charge number 1
- F
- Faraday constant C mol^-1
- phi
- electric potential V
Conditions and scope
- Use dimensionless activities and a stated standard state; single-ion quantities require a convention and cannot be independently varied in an electroneutral bulk.
Sources · 1
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Evidence and review
Electrochemistry 6.3: Chemical and electrochemical potentials: Chemical-potential/activity gradients; coupled binary diffusion and electroneutral constraints (relevant full-text sections)
2026-10-10 · Bounded author source inspection of activity and electrochemical potential gradients, including the stated conditions; independent branch review is recorded separately.
Entry details
Permanent link to this entry ↗- Record identity
- res-chem-electrochemical-gradient
- Revision
- research.1
- Structured reference record
- Postgraduate & research reference