Written by the Fiveable Content Team • Last updated September 2025
Verified for the 2026 exam
Verified for the 2026 exam•Written by the Fiveable Content Team • Last updated September 2025
Definition
Graham's Law states that the rate of effusion (or diffusion) of a gas is inversely proportional to the square root of its molar mass. In simpler terms, lighter gases will effuse or diffuse faster than heavier gases.
Effusion refers to the process by which gas particles escape from a container through a small opening. It can be thought of as similar to water leaking out of a small hole in a bucket.
Rate of Effusion: Rate of effusion is how fast gas particles escape from their container through an opening. It can be compared to how quickly people exit a crowded room when someone opens up another door.
Molar mass is the mass of one mole (Avogadro's number) of molecules or atoms in grams. It is like weighing different kinds of fruits at the grocery store - some may weigh more due to their denser composition while others may weigh less due to their lighter structure.