The rms speed of an oxygen molecule at 0°C is 460 m/s.If the molar mass of oxygen is 32 g and of helium is 4 g, then the rms speed of a helium molecule at 0°C is:
A)160 m/s
B)330 m/s
C)650 m/s
D)1300 m/s
E)3700 m/s

Question

Quizplus · Accepted Answer

The rms speed is inversely proportional to the square root of the molar mass. Since helium is 1/8th the molar mass of oxygen, its rms speed is √8 times that of oxygen, which is approximately 1300 m/s.

The Rms Speed of an Oxygen Molecule at 0°C Is