Question

The rms velocity of oxygen molecule at $ 27{}^\circ C $ is (Atomic weight of oxygen = 16)

• A. $ 402.5\,m{{s}^{-1}} $
• B. $ 400.5\text{ }m{{s}^{-1}} $
• C. $ 483.5\text{ }m{{s}^{-1}} $
• D. $ 532.5\text{ }m{{s}^{-1}} $

Answer 1

Answer: (C)

Temperature $ T=27{}^\circ C=273+27=300K $
Atomic weight of oxygen =16
$ \therefore $ Molecular weight of oxygen, $
M=2\times 16=32 $
$ R=8.31\text{ }J\text{ }mo{{l}^{-1}}{{K}^{-1}} $
So, the rms velocity, $ C=\sqrt{\frac{3RT}{M}} $
$ =\sqrt{\frac{3\times 8.31\times 300}{32}}=483.5\,m{{s}^{-1}} $