Electro Chemistry - Formula Sheet

Conduction and Resistance

V = I * R: Potential difference (V) equals Current (I) multiplied by Resistance (R).

R = ρ * (l/A): Resistance (R) depends on resistivity (ρ), length (l), and cross-sectional area (A).

κ = (1/R) * (l/A): Specific conductance (κ) is the reciprocal of resistance times the cell constant.

Molar Conductivity

Λm = (κ * 1000) / M: Molar conductivity (Λm) relates specific conductance (κ) to molarity (M).

Λ°m = ν+ λ°+ + ν- λ°-: Kohlrausch's law for calculating limiting molar conductivity from ionic contributions.

Electrochemical Cell Calculations

E°cell = E°cathode - E°anode: Calculation of standard cell EMF using reduction potentials.

ΔG° = -n * F * E°cell: Standard Gibbs free energy change where n is the number of electrons and F is Faraday's constant.

Ecell = E°cell - (0.0591 / n) * log Q: Nernst Equation at 298K where Q is the reaction quotient.

log K = (n * E°cell) / 0.0591: Relationship between the equilibrium constant (K) and the standard cell potential.

Faraday's Laws

m = Z * I * t: Mass (m) deposited equals the electrochemical equivalent (Z) times current (I) and time (t).

Z = Equivalent Mass / 96500: Definition of the electrochemical equivalent constant.