Effusion Rate Calculator
Graham's law for effusion: r1/r2 = sqrt(M2/M1). Compare effusion rates of two gases.
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Enter the molar masses of two gases. The calculator applies Graham's law: r1/r2 = sqrt(M2/M1). A ratio greater than 1 means Gas 1 effuses faster through a small hole.
About the Effusion Rate Calculator
Effusion rate follows Graham's law, identical mathematically to the diffusion rate law. Lighter gas molecules move faster on average (from the kinetic molecular theory) and therefore escape through small holes more quickly. This principle was historically used in uranium isotope separation and is fundamental to the kinetic theory of gases.
Frequently Asked Questions
What is effusion?
Effusion is the escape of gas molecules through a tiny hole (smaller than the mean free path) into a vacuum. Unlike diffusion (mixing through space), effusion involves passage through an orifice.
How was this used for uranium enrichment?
The gaseous diffusion process separated uranium-235 from uranium-238 by converting uranium to UF6 gas and passing it through porous barriers. U-235 F6 (349 g/mol) effuses slightly faster than U-238 F6 (352 g/mol). Many stages were needed because the ratio is only 1.0043.
Is effusion rate the same as diffusion rate?
Graham's law applies to both, with the same mathematical form. However, effusion is through a tiny hole while diffusion is through a gas or space. The rate ratio sqrt(M2/M1) is the same for both processes.