1. What is the Rate of Diffusion Equation?

The rate of diffusion equation estimates how quickly molecules spread through a medium. It depends on temperature, molar mass of the substance, pressure difference, and the thickness of the barrier.

2. How Does the Calculator Work?

The calculator uses the rate of diffusion equation:

Where:

• \( R \) — Gas constant (8.314 J/mol K)
• \( T \) — Absolute temperature (K)
• \( M \) — Molar mass of the substance (kg/mol)
• \( P \) — Pressure difference (Pa)
• \( thickness \) — Thickness of the barrier (m)

Explanation: The equation shows that diffusion rate increases with temperature and pressure, and decreases with molar mass and barrier thickness.

3. Importance of Diffusion Rate Calculation

Details: Calculating diffusion rates is crucial in chemical engineering, pharmaceutical design, membrane technology, and understanding biological processes like gas exchange in lungs.

4. Using the Calculator

Tips: Enter all values in SI units. Temperature must be in Kelvin (K = °C + 273.15). Molar mass should be in kg/mol (1 g/mol = 0.001 kg/mol).

5. Frequently Asked Questions (FAQ)

Q1: What factors affect diffusion rate the most?
A: Temperature and molar mass have the greatest impact as they are under the square root in the equation.

Q2: How does pressure affect diffusion?
A: Higher pressure difference directly increases the diffusion rate proportionally.

Q3: What are typical diffusion rate values?
A: Rates vary widely but are often in the range of 10^-9 to 10^-5 mol/m² s depending on the system.

Q4: When is this equation not applicable?
A: For very small molecules (like H₂), at very high pressures, or in porous media where other mechanisms may dominate.

Q5: How can I increase diffusion rate in a system?
A: Increase temperature, decrease molar mass (if possible), increase pressure difference, or decrease barrier thickness.