In a mixture of hydrogen and oxygen gases at the same temperature, wich molecules move faster?

Answer 1

I think kinetic energy is 1/2*m*v^2 so if they both have same kinetic energy (same temperature) and oxygen have greater mass its velocity would have to be slower looking at that relationship.

Answer 2

The hydrogen atoms. It's a counter-intuitive idea, but in a mixture of gases, on average they've all got about the same kinetic energy. So the lighter molecules have to move faster. But that's only on average. The molecules all move at different speeds. So a few oxygen molecules move faster than some hydrogen molecules.