What is the typical magnitude of gaseous diffusivity at standard atmospheric pressure_____________________ cm2/second?
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Answer: A. 1
Explanation
Gaseous mass diffusivity at standard atmospheric conditions typically has a magnitude around one. Molecular diffusion coefficients for common gas pairs range from zero point one to one square centimeter per second. Kinetic theory of gases predicts molecular diffusion rates based on temperature and pressure parameters. Diffusivity measures how rapidly chemical species migrate through a medium due to concentration gradients. Standard atmospheric pressure refers to one atmosphere and typical ambient room temperatures. Gas phase diffusivities are several orders of magnitude higher than liquid or solid diffusivities.
Chemical reaction engineering and mass transfer design calculations require accurate gas diffusivity values. Diffusion coefficients are essential for evaluating Sherwood and Schmidt dimensionless transport numbers. Understanding gaseous diffusivity helps model pollutant dispersion and gas absorption column performance. One to five overstates standard binary gas diffusivities which generally center near zero point one to one. Five to ten represents excessively high values not typical for standard gas pairs at atmospheric pressure. Greater than ten is unrealistic for ordinary gaseous diffusion coefficients at standard room conditions.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
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