# Electrochemical Lab

Manual Equations

**Anson Equation**- Q is charge (C)
- n is number of electrons transferred
- F is Faraday’s Constant (96,485.3 C/mol)
- A is surface area of the working electrode (cm
^{2}) - C
_{0}is initial concentration of the analyte (mol/cm^{3}) - D is diffusion coefficient of the analyte (cm
^{2}/s) - t is time (s)

**Corrosion Rate**- CR is corrosion rate in milli-inches per year (mpy)
- I
_{corr}is corrosion current (A) - K is constant that defines the units for corrosion (1.288 x 10
^{5}milli-inches/A·cm·year) - EW is equivalent weight (g/equivalent)
- d is density (g/cm
^{3}) - A is area of the electrode (cm
^{2})

**Cottrell Equation**- i is current (A)
- n is number of electrons transferred
- F is Faraday’s Constant (96,485.3 C/mol)
- A is surface area of the working electrode (cm
^{2}) - C
_{0}is initial concentration of the analyte (mol/cm^{3}) - D is diffusion coefficient of the analyte (cm
^{2}/s) - t is time (s)

**Diffusion Layer Thickness**- l is distance (cm)
- D is diffusion coefficient of the analyte (cm
^{2}/s) - t is time (s)

**Faraday’s Law of Electrolysis**- m is mass (g)
- Q is charge (C)
- M is molar mass (g/mol)
- F is Faraday’s Constant (96,485.3 C/mol)
- z is valance number

**Fick’s First Law of Diffusion**- J is diffusional flux (mol/m
^{2}s) - D is diffusion coefficient of the analyte (m
^{2}/s) - is concentration (mol/m
^{3}) - x is position (m)

- i
_{d}is diffusion limited current (A) - n is the number of electrons transferred
- F is Faraday’s Constant (96,485.3 C/mol)
- A is surface area of the working electrode (cm
^{2}) - D is diffusion coefficient of the analyte (cm
^{2}/s) - (dC/dx)
_{0}is concentration gradient at the surface of the electrode

- J is diffusional flux (mol/m
**Formal Peak Potential**- E
^{o}is the formal potential of the analyte - E
_{pc}is the cathodic peak potential - E
_{pa}is the anodic peak potential

- E
**Levich Equation**- i
_{L}is Levich current (A) - n is the number of electrons transferred
- F is Faraday’s Constant (96,485.3 C/mol)
- A is surface area of the working electrode (cm
^{2}) - D is diffusion coefficient of the analyte (cm
^{2}/s) - is the angular rotation rate of the electrode (rad/s)
- ν is the kinematic viscosity (cm
^{2}/s) - C is concentration of the analyte (mol/cm
^{3})

- i
**Nernst Equation**- E is cell potential at the temperature of interest
- E
^{o}is the standard cell potential - R is the Molar Gas Constant (8.31446 J/mol•K)
- T is temperature (K)
- n is number of electrons transferred
- F is Faraday’s Constant (96,485.3 C/mol)
- Q is the reaction quotient

**Ohm’s Law**- R is resistance
- E is applied potential
- I is applied current

**Peak-to-peak separation for reversible reaction**- n is the number of electrons transferred
- E
_{peak}is the different between the cathodic and anodic peak potentials

**Randles – Sevcik equation**- n is the number of electrons transferred
- F is Faraday’s Constant (96,485.3 C/mol)
- A is surface area of the working electrode (cm
^{2}) - D is diffusion coefficient of the analyte (cm
^{2}/s) - R is the Molar Gas Constant (8.31446 J/mol•K)
- T is temperature (K)

**Ratio of peak heights for a reversible reaction**- i
_{pc}is cathodic peak current - i
_{pa}is anodic peak current

- i
**Steady-State Current at a Microelectrode**- I is steady-state current (A)
- n is the number of electrons transferred
- F is Faraday’s Constant (96,485.3 C/mol)
- D is diffusion coefficient of the analyte (cm
^{2}/s) - C
^{b}is analyte concentration (mol/cm^{3}) - r
_{0}is radius of the electrode (cm)

**Stern Geary Equation**- I
_{corr}is corrosion current (A), - R
_{p}is polarization resistance - β
_{a}is anodic Tafel constant - β
_{c}is cathodic Tafel constant

- I