F/11.16 - Physics Help Please! RMS speed of an argon atom? ***toughest question you will see today*** HELP!!

Question

A gas consists of a mixture of neon and argon. The rms speed of the neon atoms is 450m/s.

A) What is the rms speed of the argon atoms?

???m/s

Answer 1

Oh god, the humanity!  So tough.  Must answer.

The atoms are at the same temperature, so they have the same distribution of kinetic energy.

T = 1/2 mv^2

So the square of the velocity is inversely proportional to the mass.  So the root mean square velocity is inversely proportional to the square root of the mass.

sqrt ( <vArgon^2>) = sqrt (<vNeon^2>) * sqrt (mNeon / mArgon)

So all you have to do is look up the atomic masses of Neon and Argon (atomic masses will do since Noble gases won't be in mollecules).  They give you the rms speed of Neon.  Plugnchug.