Diffusion

Diffusion is the rate at which gases in a medium mix together. Diffusion explains why if you spray a refresher in your room, it would take someone on the other side of the room some time to smell it. Eventually, gases diffuse to make a homogenous composition of mixed gas. Diffusion can occur in liquids and liquid solutions, too, but to a lesser extent.

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It may seem compelling to use Graham's Law to define relative diffusion rates but that's not always the case, especially because the two gases travel through an air medium. Because the gases collide with air, the diffusion rates increase. This makes it hard to quantify diffusion on an intuitive level.

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However, it's still worth knowing what factors affect diffusion rates. The first one is temperature, and for a simple reason: the hotter the gas, the faster the gas is on average, so the quicker the gases will mix. The second one is the distance between gases, which is related to the volume of their container. The lower the distance, the faster the diffusion rate because if the gases travel less to meet each other, they'll take less time.