Answer:
I believe the correct answer is A.
Explanation:
He atoms are smaller than Ne atoms (4AMU vs 20AMU). Although the kinetic energy and concentrations are the same (same temperature and each have 0.5 mole in 10.0L containers), the kinetic energy is a product of mass and velocity. Since the Ne mass is greater, it will have a lower speed, thus taking longer to bounce out the pinhole.
