Concentration cell

Matrix context

D = disequilibrium row · C = coupling family column. A cell reads the state of the atlas for that pair.

D.03 × C.21 · Concentration gradient × Electrochemicalfamily: Electrochemical

Typed bounds on this route

Every limit the atlas holds for this route, as constraint records: reached through bounded_by claims on the route's own entities. Hard bounds (an upper bound or a formula) decide the thermodynamic-bound check above; benchmarks, constitutive relations and resource limits are listed and never decisive. No prose limit exists anywhere (pass 42).

• Free energy of mixing · resource-bound · listed, never decisive
  W ≤ −ΔG_mix ≈ 0.8 kWh per m³ of fresh water into seawater
• Nernst / Gibbs free-energy bound · resource-bound · listed, never decisive
  W_electrical ≤ −ΔG = nFE_cell

Steps

1. 01
   Concentration gradient —drives→ Concentration cell effectestablishedclaim record

   chemical → electrical · loss to thermal

   E = (RT/zF) · ln(a₁/a₂) · RT/(zF), multiplying the dimensionless logarithm of the activity ratio (25.7 mV/z at 25 °C) [V]

   Temperature is a parameter of the coefficient, not the driving quantity; the cell is driven by the activity (concentration) ratio between the two half-cells.

   • two electrodes of the same kind in solutions of different activity joined by a salt bridge or membrane

   aqueous medium required

   refs [1]
2. 02
   Concentration cell effect —produces→ Ionic currentestablishedclaim record

   electrical → electrical

   refs [1]
3. 03
   Ionic current —converts into→ Electrical workestablishedclaim record

   electrical → electrical · loss to thermal

   • electrodes exchange the ionic current for an electronic current through the external load

   refs [1]

Evidence for the complete composition · 1

1. [1]
   A. J. Bard, L. R. Faulkner. Electrochemical Methods: Fundamentals and Applications (2nd ed.) (2001)

   Wiley · book, no DOI · record

Evidence for the constituent relations · 1

1. [1]
   A. J. Bard, L. R. Faulkner. Electrochemical Methods: Fundamentals and Applications (2nd ed.) (2001)

   Wiley · book, no DOI · record