Graham's Law Of Effusion Calculator

Compare effusion rates of gases based on their molar masses. Essential for chemistry students and professionals working with gas dynamics.

Molar Mass Gas 1 (g/mol)

Molar Mass Gas 2 (g/mol)

Results

Effusion Rate Ratio (Gas1/Gas2): 3.99

Time Ratio (Gas2/Gas1): 0.25

Gas 1 effuses 3.99 times faster than Gas 2

About Graham's Law of Effusion

Graham's Law states that the rate of effusion of a gas is inversely proportional to the square root of its molar mass. This calculator compares relative effusion rates between two gases, which is crucial in fields like chemical engineering and atmospheric science.

Calculation Steps:

Enter molar masses for both gases (in g/mol)
The rate ratio is calculated as √(M2/M1)
The time ratio is the inverse of the rate ratio

Examples:

Oxygen (32 g/mol) vs Hydrogen (2 g/mol): Rate ratio = 4.0, Hydrogen effuses 4x faster
Carbon dioxide (44 g/mol) vs Helium (4 g/mol): Rate ratio = 3.3, Helium effuses 3.3x faster

Important Notes:

Assumes ideal gas behavior and identical temperature/pressure conditions
Only valid for gases at low pressures and high temperatures
Molar masses should be entered in grams per mole (g/mol)

Common Gas Reference

Click to set as Gas 1 or Gas 2 (Shift+Click)

Frequently Asked Questions

Q: How accurate is Graham's Law?

A: It provides good approximations for ideal gases but may deviate for real gases at high pressures or low temperatures.

Q: Can I use atomic mass units instead of g/mol?

A: Yes, since the calculation uses ratios, any consistent mass unit will give the same result.

Q: Does temperature affect effusion rates?

A: Absolute rates change with temperature, but the ratio between two gases remains constant at a given temperature.

Formulas & Assumptions

Rate Ratio = √(M₂/M₁)
Time Ratio = 1/Rate Ratio = √(M₁/M₂)
      
Where:
M₁ = Molar mass of gas 1 (g/mol)
M₂ = Molar mass of gas 2 (g/mol)

Results are rounded to 4 significant figures. Uses standard SI units.

Disclaimer

For educational purposes only. Not intended for critical engineering or scientific applications. Always verify results with authoritative sources.

References

SI Brochure and ISO 80000 unit definitions
NIST Standard Reference Database
IUPAC Gold Book definitions

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Grahams Law Of Effusion Calculator

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