Graham Effusion Rate Calculator
Compare ideal molecular effusion rates and equal-condition collection times using gas molar masses.
YOUR CALCULATION
Result
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Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
Use the molecular-flow square-root molar-mass relation under equal pressure/temperature conditions.
RateA/RateB=√(MB/MA); timeA=timeB(VA/VB)√(MA/MB)
Worked example
Molar masses 2 and 32 g/mol give gas A four times the ideal volume rate; one liter of each takes 15 s versus 60 s.
Assumptions and input details
Ideal effusion through a molecular-scale aperture, not ordinary pressure-driven pipe flow. Same reference temperature/pressure, geometry and driving conditions; no mixing, collision, reaction or actual gas-handling procedure.
Unit definitions
Unit selection is independent of language. Each selector contains only units for its physical quantity. Calculations use defined base units internally.
The 36 volume definitions distinguish US liquid, US dry and Imperial measures. Cups carry an explicit definition. Japanese shō is 2401/1331 L and a gō is one tenth of it; the explicitly labelled 180 mL rice cup is separate.
Regional measures are not interchangeable merely because their names look similar. This is a documented selection, not a claim to include every historical unit.
NIST measurement tables · UK Imperial definitions · Japanese traditional units · Mainland China and Hong Kong unit distinctions
Using this calculator
Can I enter my own problem?
Yes. Replace the example values with your own inputs. The result, calculation steps, tables and applicable diagrams update from those inputs. Blank or invalid values clear the result; example values are never silently substituted for missing inputs.
Are the results exact?
Results use floating-point arithmetic and displayed rounding. Read the formula, assumptions and any stated data precision before interpreting the result.
Is my input uploaded?
The calculation runs in your browser. No account, file upload or external AI service is required. Inputs are not saved between page reloads.
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