Velocity distribution curves general inquiry

[mrjoe2]

for a graph that has the velocity as the x-axis and the number of molecules as the y axis, i know that as the number of molecules increases, the average velocity will become lower and lower, but what if the molecules being tested are in relative amounts?

for example you have air which is 78.08 percent N2, 20.95 percent O2 and .93 percent Ar by volume right. so is it just the number of molecules that determines the speed. so N2 would havethe slowest speed, then O2, then Ar.

HOWEVER, why does the equation speed = sqrt (3RT/M) depend on the MOLAR MASS of the molecule and not the number of molecules. my TA in u of t could not answer this question, i was hoping someone here could. thank you

 

[Borek]

why does the equation speed = sqrt (3RT/M) depend on the MOLAR MASS of the molecule and not the number of molecules. my TA in u of t could not answer this question, i was hoping someone here could. thank you

Huh? Why does the speed of the car depend on its make, and not on the number of cars?

Do you know the difference between extensive and intensive properties?

 

[Blueshift5]

The velocity distribution curve is a representation of the range of velocities that molecules in a sample can have. As the number of molecules increases, the curve will shift towards lower velocities, as there will be a greater number of slower-moving molecules in the sample. However, the relative amounts of different types of molecules in the sample will also affect the shape of the curve.

In the example you provided, the different types of molecules (N2, O2, and Ar) will have different average velocities due to their different molar masses. This is because the speed of a molecule is directly related to its mass, as shown in the equation speed = sqrt(3RT/M). Therefore, even if there are the same number of molecules of each type in the sample, the N2 molecules will have a slower average velocity compared to O2 and Ar due to its higher molar mass.

The reason why the equation for speed depends on the molar mass rather than the number of molecules is because it takes into account the mass of the individual molecules, not just their number. This is important because even if two samples have the same number of molecules, they can have different molar masses and therefore different average velocities.

I hope this helps to clarify the relationship between velocity, number of molecules, and molar mass in the velocity distribution curve. If you have any further questions, please feel free to ask.