The Rms Speed of a Certain Sample of Carbon Dioxide

Multiple Choice

The rms speed of a certain sample of carbon dioxide molecules, with a molecular weight of 44.0 g/mole, is 396 m/s. What is the rms speed of water vapor molecules, with a molecular weight of 18.0 g/mol, at the same temperature as the carbon dioxide?

A) 253 m/s
B) 619 m/s
C) 506 m/s
D) 421 m/s
E) 387 m/s