The same speed for different gas molecules in a same tubing(Dec. 28th Sign )

i think so

I think that it depends on the gas concentration or the pressure .

应助达人

I don't know， but I think that big molecular or heavy molecular may flow slowly than small one or light one.

If the heavy ones move slowly, then collision will take place between the faster and the slower. At last ,if moving path is long enough, speed between the heaveier and the lighter molecule will be no difference. But maybe not the same speed.