 ## General Chemistry

Learn the toughest concepts covered in Chemistry with step-by-step video tutorials and practice problems by world-class tutors

7. Gases

# Velocity Distributions

Velocity Distributions represent probability distributions for a gas when examining their molar mass and temperature.

Velocity Distribution Curves
1
concept

## Velocity Distributions 2m
Play a video:
the shape of the Maxwell bolts man distribution curve is dependent on two factors temperature and molecular weight. So for the first factor temperature, we have two curves, ones at 30°C and one's at 330°C. If we look at the apex with the very top of each curve, we have our probable speed. Remember the probable speed is where a majority of the gasses will reside. The velocity in which they move. What we should see here is that for the curve at a higher temperature, The probable speed where a majority of them was moving looks like it's around 600 m/s. But the probable speed for the curve at a lower temperature Is only around 400 or so meters per second. So what trend can we see here? What we can see here that as my temperature increases the molecules moving at a higher velocity also increase. If we take a look here for the green curve, we have just in this little portion here, this many gasses moving At 800 m/s or higher. Not a great amount, but if we increase the temperature two, we see we have a bigger chunk of gasses moving at m/s or greater. That's what happens, increasing the temperature, increase the velocity of many of the gasses within each curve. So from this we can say as the temperature also increases the curve gets more broad and lower. So more gasses are able to move at a higher velocity. That's also what it's showing Factor two We have molecular weight. So for factor too, We have four curves for four gasses. We have helium which is around four grams per mole Neon, which is around 20 g per mole Argon which is around 40 g from all or so. And finally Xenon, which is around 131 g per mole. What can we see here? Well, for helium, we can see that it's probable speed is around 700 or so meters per second and then for Xenon, the one that wins the most, it's probable speed is only around 100 or so meters per second. So which brand can we make here? Well, the trend we see here is that as the molecular weight increases, molecules moving at a higher velocity decreases. So if you wait more as a gas, it's harder for you to propel yourself, move yourself and that's what we're seeing. Helium weighs at least. So it's it's easier for it to move faster around Now. As a result of this, Also, in terms of molecular weight, we can see that helium, which weighs the least, also has the most broad her. So we can say here, as the molecular weight decreases, the curve gets more broad and lower meaning more gasses are able to get to a certain type of velocity as everyone else. Right? So these are the trends we need to realize when it comes to gaseous molecules when we factor in the effects of temperature and molecular weight on their velocities.
2
example

## Velocity Distributions Example 1 2m
Play a video: 