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Molecular Diffusivity of Mass is the spread of momentum between particles (atoms or molecules) of matter, often in the fluid state. It represents how quickly mass diffuses through a medium.
The calculator uses the formula:
Where:
Explanation: This formula relates the diffusivity of mass to the diffusivity of momentum through the Schmidt number, which is the ratio of momentum diffusivity to mass diffusivity.
Details: Calculating molecular diffusivity of mass is crucial in various engineering and scientific applications, particularly in fluid dynamics, mass transfer operations, and chemical process design where diffusion processes play a significant role.
Tips: Enter molecular diffusivity of momentum in m²/s and Schmidt number (dimensionless). Both values must be positive numbers greater than zero.
Q1: What is the physical significance of Schmidt number?
A: Schmidt number represents the ratio of momentum diffusivity to mass diffusivity, indicating the relative effectiveness of momentum and mass transport by diffusion in fluid flow.
Q2: What are typical values for molecular diffusivity?
A: Molecular diffusivity values vary widely depending on the substance and medium. For gases, typical values range from 10⁻⁵ to 10⁻⁴ m²/s, while for liquids, values are typically between 10⁻⁹ to 10⁻¹⁰ m²/s.
Q3: How does temperature affect molecular diffusivity?
A: Molecular diffusivity generally increases with temperature. For gases, diffusivity is approximately proportional to T¹.⁵, while for liquids, the relationship is more complex but generally shows increasing diffusivity with temperature.
Q4: What are the limitations of this calculation?
A: This calculation assumes ideal conditions and may not account for factors like concentration gradients, pressure variations, or complex molecular interactions that can affect diffusivity in real-world scenarios.
Q5: In which engineering applications is this calculation most useful?
A: This calculation is particularly useful in chemical engineering for designing separation processes, in environmental engineering for modeling pollutant dispersion, and in materials science for studying diffusion processes.