Question

If the $v_{rms}$ is $30R^{1/2}$ at $27^{\circ }C$ then calculate the molar mass of gas in kilogram

• A. $l$
• B. $2$
• C. $4$
• D. $0.001$

Answer 1

Answer: (D)

$v_{rms}=\sqrt{\frac{3RT}{M}}$
$\sqrt{30^{2}R}=\sqrt{\frac{3RT}{M}}$
$\Rightarrow 30\times 30R=\frac{3R\times 300}{M}$
$\Rightarrow M=\frac{3\times 300}{30\times 30}1g$
$=0.001Kg$