Molecular Speeds: the Root-Mean-Square Speed (Thermal Speed) of a Certain

Multiple Choice

Molecular speeds: The root-mean-square speed (thermal speed) of a certain sample of carbon dioxide molecules, with a molecular weight of 44 g/mol, is 396 m/s. What is the root-mean-square speed (thermal speed) of water vapor molecules, with a molecular weight of 18 g/mol, at the same temperature?

A) 253 m/s
B) 396 m/s
C) 421 m/s
D) 506 m/s
E) 619 m/s