Molar Flux of Diffusing Component A Through Non-Diffusing B Based on Mole Fractions of A Calculator

Formula Used:

\[ N_a = \frac{D \cdot P_t}{\delta} \cdot \ln\left(\frac{1 - y_{a2}}{1 - y_{a1}}\right) \]

Diffusion Coefficient (DAB):

m²/s

Total Pressure of Gas:

Film Thickness:

Mole Fraction of Component A in 1:

Mole Fraction of Component A in 2:

Molar Flux of Diffusing Component A (Nₐ):

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1. What is Molar Flux of Diffusing Component A?

The molar flux of diffusing component A represents the amount of substance A that diffuses through a unit area per unit time in a binary mixture where component B is non-diffusing. This calculation is essential in mass transfer operations and chemical engineering processes.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ N_a = \frac{D \cdot P_t}{\delta} \cdot \ln\left(\frac{1 - y_{a2}}{1 - y_{a1}}\right) \]

Where:

\( N_a \) — Molar flux of diffusing component A (mol/(s·m²))
\( D \) — Diffusion coefficient (m²/s)
\( P_t \) — Total pressure of gas (Pa)
\( \delta \) — Film thickness (m)
\( y_{a1} \) — Mole fraction of component A at position 1
\( y_{a2} \) — Mole fraction of component A at position 2

Explanation: This equation calculates the molar flux of component A through a stagnant (non-diffusing) component B based on the logarithmic mean concentration difference.

3. Importance of Molar Flux Calculation

Details: Accurate calculation of molar flux is crucial for designing separation processes, mass transfer equipment, and understanding diffusion phenomena in chemical engineering applications.

4. Using the Calculator

Tips: Enter diffusion coefficient in m²/s, total pressure in Pa, film thickness in m, and mole fractions (values between 0 and 1). All values must be valid and positive.

5. Frequently Asked Questions (FAQ)

Q1: What does it mean when component B is non-diffusing?
A: Component B is considered non-diffusing or stagnant when it has zero net molar flux, meaning it doesn't move relative to the chosen frame of reference.

Q2: When is this equation applicable?
A: This equation applies to steady-state diffusion of component A through stagnant component B in gas mixtures at constant temperature and pressure.

Q3: What are typical units for the diffusion coefficient?
A: The diffusion coefficient is typically measured in m²/s, though cm²/s is also commonly used in some contexts.

Q4: How does temperature affect the diffusion coefficient?
A: The diffusion coefficient increases with temperature, typically following an Arrhenius-type relationship.

Q5: What limitations does this equation have?
A: This equation assumes ideal gas behavior, constant total pressure, isothermal conditions, and that component B is truly non-diffusing.