Graham's Law

Gases are in constant motion and collide with each other and the walls of their container. These containers may have small holes or pores in them which allow the gas to escape. Due to the random, constant motion of the gases, some of the molecules may be able to escape the container.  This process of passing through a small pore is known as effusion. The speed at which effusion occurs depends on a few things: the temperature and the molecular mass of the gas. In this topic, you will investigate Graham’s Law, which compares the rates of effusion of two different gases.

Essential Question

• How does Graham’s Law allow you to compare the rates of effusion of two different gases?