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21. Kinetic Theory of Ideal Gases

Kinetic-Molecular Theory of Gases


Introduction to Kinetic-Molecular Theory

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Hey guys. So in previous videos we've seen the equations for ideal gasses in the next couple of videos, we're going to see some other equations like for speeds and energies and distances that are also for ideal gasses. But these things are special because they make up what's called the kinetic molecular theory. This is a term that you might see in your classrooms and textbooks. So I want to briefly explain to you what this kinetic molecular theory is and why it's helpful for us. Let's check this out basically what it is. It's just a set of equations and these equations connect the variables that we've seen so far, like pressure, volume and temperature for ideal gasses with the kinetics meaning just the motion of ideal gas molecules. That's why it is called the kinetic molecular theory. Basically what these equations do is they help us connect the macroscopic variables. Macroscopic just means large scale variables to microscopic variables, meaning small scale. So, for example, if I have a container of gas, the macroscopic large scale variables are the things that we can measure about the gas as a whole. These are basically just the very easy to measure variables like pressure, volume and temperature. We use barometers and thermometers to measure these kinds of things. But basically with this kinetic molecular theory says, is that these variables are actually related to the motions and the microscopic properties of the particles in themselves that are all moving inside of this container. So for example, these things are moving around with some speeds and energies and these things are much harder to measure. We can't just go in there and single out a specific atom and measure its speed because there are trillions of them. So these are much harder to measure here. So basically we're gonna, what we're gonna need this kinetic molecular theory for is we're gonna need it to connect or express the speeds and energies of particles in terms of the variables that we've seen so far for ideal gasses, like pressure, volume and temperature. So that's really all there is to it. Let's go ahead and take a look at these equations.