Browse Questions

If $U_{rms} is\; 30 R^{\large\frac{1}{2}}\; at \;27^{\large\circ}$ then the molar mass of the gas in kg is

$(a)\;1\qquad(b)\;2\qquad(c)\;0.004\qquad(d)\;0.001$

Can you answer this question?

$U_{rms} = \sqrt{\large\frac{3RT}{M}}$
$(or) 30R^{\large\frac{1}{2}}= \sqrt{\large\frac{3RT}{M}}$
$(or) (30)^2 = \large\frac{300\times3}{M}$
$M = 1.0 g\; mol^{-1}$
$=0.001 kg \;mol^{-1}$
Hence answer is (d)
answered Mar 3, 2014