Molar Flux of Diffusing Component A through Non-Diffusing B based on Partial Pressure of B Calculator

Molar Flux Formula:

\[ N_A = \frac{D_{AB} \cdot P_t}{R \cdot T \cdot \delta} \cdot \ln\left(\frac{P_{B2}}{P_{B1}}\right) \]

Diffusion Coefficient (D_AB):

m²/s

Total Pressure of Gas (P_t):

Temperature of Gas (T):

Film Thickness (δ):

Partial Pressure of B in 2 (P_B2):

Partial Pressure of B in 1 (P_B1):

Molar Flux of Diffusing Component A (N_A):

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1. What is Molar Flux of Diffusing Component A?

Definition: Molar flux (N_A) is the amount of substance (in moles) that diffuses through a unit area per unit time.

Purpose: This calculator determines the molar flux of component A through non-diffusing component B based on the partial pressures of B.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ N_A = \frac{D_{AB} \cdot P_t}{R \cdot T \cdot \delta} \cdot \ln\left(\frac{P_{B2}}{P_{B1}}\right) \]

Where:

\( N_A \) — Molar flux of component A (mol/(s·m²))
\( D_{AB} \) — Diffusion coefficient (m²/s)
\( P_t \) — Total pressure of gas (Pa)
\( R \) — Universal gas constant (8.314 J/(mol·K))
\( T \) — Temperature (K)
\( \delta \) — Film thickness (m)
\( P_{B2} \) — Partial pressure of B at point 2 (Pa)
\( P_{B1} \) — Partial pressure of B at point 1 (Pa)

Explanation: The formula calculates the molar flux based on the logarithmic mean partial pressure difference of component B.

3. Importance of Molar Flux Calculation

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

4. Using the Calculator

Tips: Enter all required parameters with appropriate units. Default values are provided for reference. All values must be positive.

5. Frequently Asked Questions (FAQ)

Q1: What is the physical significance of the diffusion coefficient?
A: The diffusion coefficient (D_AB) measures how easily component A diffuses through component B under a concentration gradient.

Q2: Why do we use partial pressures of component B to calculate flux of component A?
A: This approach is valid when component B is non-diffusing (stationary), and the flux is driven by the concentration gradient of B.

Q3: What are typical values for the diffusion coefficient?
A: For gases, typical values range from 10^-6 to 10^-5 m²/s, while for liquids they're typically 10^-10 to 10^-9 m²/s.

Q4: How does temperature affect molar flux?
A: Higher temperatures generally increase diffusion coefficients and thus increase molar flux, though the exact relationship depends on the system.

Q5: What is the film thickness in this context?
A: The film thickness represents the effective distance over which the concentration gradient exists in the diffusion process.