Graham’s Law of Effusion Calculator
💨 Gas Laws & Fluids. Use the Graham’s law of effusion formula to find rate ratio r₁/r₂, molar mass gas 1, molar mass gas 2: pick the value you want, type the others, and the answer updates as you go.
Pick the ○ next to the value you want to find, fill in the others, and it solves as you type.
What each letter means
| Quantity | Unit |
|---|---|
| Rate ratio r₁/r₂ | no unit |
| Molar mass gas 1 | g/mol |
| Molar mass gas 2 | g/mol |
Worked example
Find the rate ratio r₁/r₂ when Molar mass gas 1 = 2 g/mol, Molar mass gas 2 = 32 g/mol.
Using r1/r2 = √(M2/M1): Rate ratio r₁/r₂ = 4.
Frequently asked questions
What is the formula for Graham’s law of effusion?
r1/r2 = √(M2/M1).
What do the letters stand for, and what units are used?
Rate ratio r₁/r₂, Molar mass gas 1 in g/mol, Molar mass gas 2 in g/mol.
How do you calculate rate ratio r₁/r₂?
Put the values into r1/r2 = √(M2/M1). For example, with Molar mass gas 1 = 2 g/mol, Molar mass gas 2 = 32 g/mol, rate ratio r₁/r₂ = 4.
Can I solve for a different value?
Yes. In the calculator above, pick the circle next to any value (rate ratio r₁/r₂, molar mass gas 1, molar mass gas 2) and fill in the others: it rearranges the formula for you.
