Question

Consider molecules of hydrogen gas and molecules of heavier oxygen gas that have the same kinetic energy. The molecules with the greater speed are

A) Hydrogen gas
B) Oxygen gas
C) Both have the same speed
D) Cannot be determined

Answer 1

Hydrogen gas molecules will have a greater speed than oxygen gas molecules if both have the same kinetic energy because they are lighter, and lighter gas molecules have higher speeds at the same kinetic energy.

Step-by-step explanation:

If molecules of hydrogen gas and molecules of oxygen gas have the same kinetic energy, the molecules with the greater speed are hydrogen gas. This is because kinetic energy is a function of both mass and velocity, specifically defined by the equation KE = ½ mv², where 'm' is mass and 'v' is velocity. Since the oxygen molecules are heavier, they will have a slower speed to maintain the same kinetic energy as the lighter hydrogen molecules.In terms of ideal gas behavior, at a given temperature, all gases have the same average kinetic energy (KEavg) for their molecules. Hence, the gas composed of lighter molecules (hydrogen) will have a higher root mean square speed (Urms) compared to heavier molecules (oxygen).