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Rate of Effusion Calculator

Rate of Effusion Calculator

Calculate gas effusion and diffusion rates using Graham's law of diffusion

Calculate Rate of Effusion

Gas 1

Gas 2

Calculated automatically

Graham's Law Results

Enter the required values to see Graham's law calculations

Common Gas Examples

Hydrogen (H₂)
H₂
2.016
g/mol
Helium (He)
He
4.003
g/mol
Methane (CH₄)
CH₄
16.043
g/mol
Ammonia (NH₃)
NH₃
17.031
g/mol
Water vapor (H₂O)
H₂O
18.015
g/mol
Neon (Ne)
Ne
20.18
g/mol

Quick Load: Click on any gas to load its molar mass into the calculator

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Graham's Law

Basic Formula

rate₁ / rate₂ = √(M₂ / M₁)

Rate is inversely proportional to square root of molar mass

Key Principle

Lighter gases diffuse and effuse faster than heavier gases

Applications

  • • Gas separation processes
  • • Isotope enrichment
  • • Molecular weight determination
  • • Gas leak detection

Diffusion vs Effusion

Diffusion

Gases spread from high to low concentration areas through intermolecular collisions

Effusion

Gas molecules escape through tiny openings without collisions

Speed Rankings

Hydrogen (H₂)Fastest
Helium (He)Very Fast
Methane (CH₄)Fast
Oxygen (O₂)Medium
Xenon (Xe)Slow

Understanding Graham's Law of Diffusion

What is Graham's Law?

Graham's law states that the rate of diffusion or effusion of a gas is inversely proportional to the square root of its molar mass. This fundamental principle explains why lighter gases move faster than heavier ones under the same conditions.

Historical Background

Formulated by Scottish chemist Thomas Graham in 1846, this law revolutionized our understanding of gas behavior and became crucial for industrial applications like isotope separation.

Mathematical Foundation

  • Based on kinetic molecular theory
  • Assumes ideal gas behavior
  • Equal kinetic energies at same temperature
  • Inverse relationship with molecular mass

Derivation from Kinetic Theory

½m₁v₁² = ½m₂v₂² (Equal kinetic energies)

v₁/v₂ = √(m₂/m₁) (Velocity ratio)

rate₁/rate₂ = √(M₂/M₁) (Rate ratio)

Real-World Applications

  • Uranium Enrichment: Separating U-235 from U-238
  • Gas Chromatography: Analytical separation techniques
  • Natural Gas Processing: Helium separation
  • Medical Applications: Anesthetic gas behavior
  • Environmental Science: Gas leak detection

Important: Graham's law assumes ideal conditions. Real gases may deviate at high pressures or low temperatures.

Industrial Applications

Isotope Separation

Used in nuclear fuel processing to separate uranium isotopes based on their mass differences.

Gas Purification

Industrial separation of gas mixtures by exploiting different diffusion rates.

Analytical Chemistry

Determining molecular weights of unknown gases through comparative effusion studies.

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