I have a theoretical question which I would like to brainstorm, and would appreciate any assistance. Let's say sound waves are propagated through a gas, with two types of atoms with very different mass, different by say a factor of ten. The number of particles per unit volume is equal, as are there temperatures. The gas is collisional. I would like to know if the sound wave causes one species to go faster than the other, and if so, how much faster?