Equal amounts of neon ( ) and xenon ( ) gases are each sealed in separate
CHEMISTRY · Single correct · AP · Chemistry · Properties of Substances and Mixtures · Properties of Substances and Mixtures
Problem
Equal amounts of neon (M=20.2g mol−1) and xenon (M=131g mol−1) gases are each sealed in separate, identical rigid containers at 298K. Which statement best compares the root-mean-square (rms) molecular speeds in the two samples?
(a) The rms speeds are identical because, for any ideal gas, molecular speed depends only on temperature.
(b) Xenon atoms have the higher rms speed because their larger mass allows them to carry more kinetic energy at the same temperature.
(c) Neon atoms have the higher rms speed because, at equal temperature, molecules with the smaller molar mass move faster to have the same average kinetic energy.
(d) Neon atoms have the lower rms speed because lighter molecules collide less often and therefore transfer less kinetic energy.