posted by Mary .
Gas particles travel at speeds of up to 500 m/s. Why, then, does it take so long for gas molecules to travel the length of a room?
My answer would be that the molecules still have a weak attraction to each other and, in addition, the friction of the molecules surrounding the gas, which are in the atmosphere, impede the gaseous molecules' movement across the room. Is this correct?
I think everything you say is true; however, I think you are hitting around the answer and not hitting the answer on the nose. I think the primary reason is that the gas molecules bump into oxygen and nitrogen molecules of the air and that keeps them from being able to move directly from one side of the room to the other. I think friction and the weak attraction for the molecules for each other are so small that those forces are negligible when compared to the main problem. The gas molecules can't travel more than a few nanometers (if that much) without hitting an oxygen or nitrogen molecule of the air.