So when it comes to the state of matter, in terms of gasses realize that a gas that exists by itself. In fact, it's a collection of molecules or atoms that are in constant motion. And we're going to say with this collection of gaseous molecules or atoms, there's some terms that you need to keep in mind. We have mean free path fusion versus diffusion now mean free path. This is just the average distance traveled by gas molecules between their collisions. Remember gas molecules are very far apart and spread apart within a container, but they do come into contact with one another because they're bouncing around. They're going to interact. Now, a mean free path is just the distance between two gas particles before they collide when it comes to infusion and diffusion, there are some differences. Now here we have images for a fusion versus diffusion for a fusion. This is just the escape of gaseous molecules or gas molecules or atoms through a pinhole. So the opening is very small because this opening is very small. That means these gasses typically exit the container in a one by one fashion. Okay, it's not all of them coming out at once. It's one by one for diffusion though, diffusion is just the motion of a gas mixture from a high to low concentration. So this means a couple of different things. The gas molecules may not necessarily try to leave the container. Remember, they're going from an area of high concentration to an area of low concentration. If inside is high concentration, then the gas molecules will escape to go outside. But if outside is higher concentration, then some gas could actually go into the container. So that's a big difference from a fusion. In a fusion, you're only going out for diffusion. It's all based on concentration, you're always going to the area that has lower concentration, whether that's inside or outside the container, secondly, for diffusion, the opening is bigger and because this opening is bigger, more than one gas molecule can exit at a time or enter at a time. Okay, so those are the subtle differences between infusion and infusion. Remember, a gas particle doesn't exist by itself. It's a collection of gasses. There are other gasses around the vicinity. Okay, so keep this in mind when talking about the behavior of any particular gas that you may read about.