So remember the kinetic molecular theory is a way that we try to understand ideal gas laws if they did exist. Remember, ideal gas laws themselves are completely imaginary. With the kinetic molecular theory we have 3 postulates. Postulate 1 deals with the volume of these ideal gas molecules. Here we're going to say under the first postulate, the size of the particle is significantly smaller and negligible, meaning not important, when compared to the volume of the container. Here we're going to say the volume of a gas particle itself represents less than 0.01% of the total volume in the container. So, a simple gas molecule particle doesn't take up very much space at all, so much in fact that its volume is not important. Here I'm showing the gas molecules in a larger format so we can better see them. But in actuality, they're going to be incredibly incredibly small, each one.
Postulate 2 deals with temperature. We're going to say, here under postulate 2, as the temperature increases, molecules moving at higher velocities will also increase. Here we have the root mean square speed for 3 curves, 3 gases. And here, we're going to say that each of these curves can be found at different temperatures. So let's say that this one here is at 330 degrees Celsius. We'd say that this one here is at 200 degrees Celsius, and let's say here that this one here is at 25 degrees Celsius. Actually, let's make this 100, bigger differences in temperature. Their differences in temperature will result in different overall speeds or velocities for the gas molecules. Here the root mean square speed is just under 1000 here. Here it's just between 600 and 100, and here it's just over 400 meters per second. As the temperature is increasing for each of the curves, we see that their speed or velocity is higher.
Finally, the final and third postulate deals with the forces of gases. Here we say that the collisions between gas particles and the walls of the container are completely elastic if we were to imagine ideal gases. Now, what does it mean to be elastic? Well, that means that these ideal gas particles will behave as though they have no attractive or repulsive forces between the gas around them and the walls of the container. So, a good way to think about this is, if you've ever watched ping pong balls within a container bouncing around, that's kind of an elastic collision. They're bouncing around, hitting the walls, hitting each other, but they're not sticking together. They're not pushing each other away, they're just moving around with their own momentum moving around, moving around, and that's what we talk about with ideal gas laws and ideal gases behaving elastically. They may bump into each other, but there's no repulsive or attractive forces between those gas molecules.
Right? So these are the 3 postulates that we use for us to better understand if ideal gas did exist; these are the behaviors that they would have.