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

Multiple Choice

Molecular speeds: The root-mean-square speed (thermal speed) of the molecules of a gas is 200 m/s at a temperature 23.0°C. What is the mass of the individual molecules? The Boltzmann constant is 1.38 × 10^-23 J/K.

A) 2.13 × 10^-25 kg
B) 2.45 × 10^-25 kg
C) 5.66 × 10^-25 kg
D) 1.78 × 10^-25 kg
E) 3.11 × 10^-25 kg