at room temperature a diatomic is found to have an r.m.s speed of 1930 m/s the gas is;

${{v}_{rms}}^{2}=\frac{3RT}{M}\phantom{\rule{0ex}{0ex}}Where,M=molarmass\phantom{\rule{0ex}{0ex}}So,\phantom{\rule{0ex}{0ex}}M=\frac{3RT}{{{v}_{rms}}^{2}}$

Now, at room temperature (298 K), R = 8.314 kg m

^{2}s

^{-1}

Putting the values we get:

$M=\frac{3\times 8.314\times 298}{(1930{)}^{2}}=0.002Kg=2g$

So, the gas is hydrogen (H

_{2}) with molar mass 2 g.

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