## How to Calculate and Solve for Mobility of an Ionic Specie | Electrical Properties

The image of mobility of an ionic specie is shown below.

To compute for mobility of an ionic specie, five essential parameters are needed and these parameters are Valence (nI), Electrical Charge (e), Diffusion Coefficient (DI), Boltzmann’s Constant (K) and Temperature (T).

The formula for calculating the mobility of an ionic specie:

μI = nIeDI/KT

Where:

μI = Mobility of an Ionic Specie
nI = Valence
e = Electrical Charge
DI = Diffusion Coefficient
K = Boltzmann’s Constant
T = Temperature

Let’s solve an example;
Find the mobility of an ionic specie when the valence is 18, the electrical charge is 9, the diffusion coefficient is 12, the boltzmann’s constant is 6 and the temperature is 3.

This implies that;

nI = Valence = 18
e = Electrical Charge = 9
DI = Diffusion Coefficient = 12
K = Boltzmann’s Constant = 6
T = Temperature = 3

μI = nIeDI/KT
μI = (18)(9)(12)/(6)(3)
μI = 1944/18
μI = 108

Therefore, the mobility of an ionic specie is 108 m²/(V. s).

## How to Calculate and Solve for Permeability due to Partial Pressure | Mass Transfer

The image above represents permeability due to partial pressure.

To compute for permeability due to partial pressure, three essential parameters are needed and these parameters are Diffusion Coefficient (D), Constant (K) and Partial Pressure (Po).

The formula for calculating permeability due to partial pressure:

P = DK / √(Po)

Where:

P = Permeability due to Partial Pressure
D = Diffusion Coefficient
K = Constant
Po = Partial Pressure

Let’s solve an example;
Find the permeability due to partial pressure when the diffusion coefficient is 12, the constant is 14 and the partial pressure is 17.

This implies that;

D = Diffusion Coefficient = 12
K = Constant = 14
Po = Partial Pressure = 17

P = DK / √(Po)
P = (12)(14) / √(17)
P = 168 / 4.12
P = 40.74

Therefore, the permeability due to partial pressure is 40.74.

Calculating the Diffusion Coefficient when the Permeability due to Partial Pressure, the Constant and the Partial Pressure is Given.

D = P x √(Po) / K

Where;

D = Diffusion Coefficient
P = Permeability due to Partial Pressure
K = Constant
Po = Partial Pressure

Let’s solve an example;
Find the diffusion coefficient when the permeability due to partial pressure is 12, the constant is 8 and the partial pressure is 16.

This implies that;

P = Permeability due to Partial Pressure = 12
K = Constant = 8
Po = Partial Pressure = 16

D = P x √(Po) / K
D = 12 x √(16) / 8
D = 12 x 4 / 8
D = 48 / 8
D = 6

Therefore, the diffusion constant is 6.

## How to Calculate and Solve for Diffusion Coefficient | Mass Transfer

The image above represents diffusion coefficient.

To compute for diffusion coefficient, three essential parameters are needed and these parameters are Constant (BA), Boltzmann’s Constant (KB) and Temperature (T).

The formula for calculating diffusion coefficient:

DA = BAKBT

Where:

DA = Diffusion Coefficient | Nernst-Einstein Equation
BA = Constant
KB = Boltzmann’s Constant
T = Temperature

Let’s solve an example;
Find the diffusion coefficient when the constant is 21, the boltzmann’ s constant is 1.39e-23 and temperature is 12.

This implies that;

BA = Constant = 21
KB = Boltzmann’s Constant = 1.3806e-23
T = Temperature = 12

DA = BAKBT
DA = (21)(1.38e-23)(12)
DA = 3.47

Therefore, the diffusion coefficient is 3.47e-21 cm²/s.

Calculating the Constant when the Diffusion Coefficient and the Temperature is Given.

BA = DA / KB x T

Where;

BA = Constant
DA = Diffusion Coefficient | Nernst-Einstein Equation
KB = Boltzmann’s Constant
T = Temperature

Let’s solve an example;
Find the constant when the diffusion coefficient is 10 and the temperature is 3.

This implies that;

DA = Diffusion Coefficient | Nernst-Einstein Equation = 10
KB = Boltzmann’s Constant = 1.3806e-23
T = Temperature = 12

BA = DA / KB x T
BA = 10 / 1.3806e-23 x 12
BA = 10 / 1.70e-9
BA = 5.88e+9

Therefore, the constant is 5.88e+9.

## How to Calculate and Solve for Chemical Breakthrough Time | Material Selection

The image above represents chemical breakthrough time.

To compute for chemical breakthrough time, two essential parameters are needed and these parameters are Thickness (l) and Diffusion Coefficient (D).

The formula for calculating chemical breakthrough time:

tb = /6D

Where:

tb = Chemical Breakthrough Time
l = Thickness
D = Diffusion Coefficient

Let’s solve an example;
Find the chemical breakthrough time when the thickness is 14 and the diffusion coefficient is 7.

This implies that;

l = Thickness = 14
D = Diffusion Coefficient = 7

tb = / 6D
tb = 14²/6(7)
tb = 196/42
tb = 4.66

Therefore, the chemical breakthrough time is 4.66 s.

Calculating the Thickness when the Chemical Breakthrough Time and the Diffusion Coefficient is Given.

l = √tb x 6D

Where;

l = Thickness
tb = Chemical Breakthrough Time
D = Diffusion Coefficient

Let’s solve an example;
Find the thickness when the chemical breakthrough time is 5 and the diffusion coefficient is 20.

This implies that;

tb = Chemical Breakthrough Time = 5
D = Diffusion Coefficient = 20

l = √tb x 6D
l = √5 x 6(20)
l = √5 x 120
l = √600
l = 24.49

Therefore, the thickness is 24.49.