💨 Graham’s Law of Effusion Calculator
Compare how fast two gases effuse (escape through a small opening) using Graham’s Law of Effusion, based on their molar masses.
What Graham’s Law describes
Graham’s Law of Effusion states that lighter gas molecules effuse (escape through a tiny opening into a vacuum) faster than heavier ones under the same conditions of temperature and pressure. It explains everyday observations like helium leaking out of a balloon faster than the surrounding air can leak in.
The formula
The law is expressed as rate1 ÷ rate2 = √(M2 ÷ M1), where rate1 and rate2 are the effusion rates of two gases and M1 and M2 are their molar masses. This calculator takes the molar masses of two gases plus a known effusion rate for Gas 1, and uses the ratio to solve for the rate of Gas 2.
Note: Graham’s Law strictly applies to effusion (movement through a very small opening) rather than general diffusion, and assumes ideal gas behavior at constant temperature and pressure. This tool is intended for general chemistry education and problem-solving.