Binary gas diffusivity D is related to system pressure (P) through the expression__________________?
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Answer: C. D ∝ 1/P
Explanation
According to kinetic theory gas diffusion models, binary gas diffusivity is inversely proportional to total system pressure. Higher pressure increases molecular density, leading to more frequent collisions and shorter mean free paths. This inverse relationship is a cornerstone of gas phase mass transfer calculations and engineering correlations. Pressure directly affects the concentration and collision frequency of molecules in a gas phase mixture. Kinetic theory derives transport coefficients by analyzing molecular velocities and mean free path lengths. Standard conditions provide a baseline for adjusting diffusion coefficients to different operating pressures.
High pressure synthesis reactors require pressure-corrected diffusion coefficients to model mass transport accurately. Vacuum distillation and absorption columns alter mass transfer rates significantly by manipulating operating pressure. Environmental scrubbers account for atmospheric pressure variations when calculating pollutant absorption rates. A positive fractional pressure dependence would incorrectly suggest that higher pressures enhance gas diffusion. Square root inverse pressure dependence underestimates the true density-driven collision frequency in gases. A power of one point five overcorrects for pressure effects compared to rigorous kinetic theory derivations.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
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