## A molar volume of gas has a density of 1.7824 . g . L^-1 at STP. What is the molecular mass of this gas?

Answer 1:

Well the molar volume of an Ideal Gas at \(STP\) is \(22.4 \cdot L\)

Explanation:

We assume Ideal Gas behaviour……….

And thus, at \(STP\), we have gots a molar mass of……..

\(22.414 \cdot L \cdot \mathrm{mol}^{-1} \times 1.7824 \cdot g \cdot L^{-1}=39.95 \cdot g \cdot \mathrm{mol}^{-1} \ldots \ldots\)

You should be able to identify this gas \(\text { pdq. }\).

Answer 2:

we know , 22.4 L of any gas gas at STP is 1 mol of the gas.

We have been given that the density of an elemental gas is 1.7824g/L at STP.

Hence mass of 22.4 L of the elemental gas gas at STP is its molar mass.

Hence molar mass \(=22.4 \frac{L}{\mathrm{~mol}} \times 1.7824 \frac{g}{L} \approx 39.9258 \mathrm{~g} / \mathrm{mol}\)