Question

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*L`

Explanation:

We assume Ideal Gas behaviour..........

And thus, at `STP`, we have gots a molar mass of........

`22.414*L*mol^-1xx1.7824*g*L^-1=39.95*g*mol^-1`......

You should be able to identify this gas `"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 `=22.4L/"mol"xx1.7824g/L~~39.9258g"/"mol`