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

Jul 7, 2017

Well the molar volume of an Ideal Gas at $S T P$ is $22.4 \cdot L$

#### Explanation:

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

And thus, at $S T P$, we have gots a molar mass of........

$22.414 \cdot L \cdot m o {l}^{-} 1 \times 1.7824 \cdot g \cdot {L}^{-} 1 = 39.95 \cdot g \cdot m o {l}^{-} 1$......

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

Jul 7, 2017

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 $= 22.4 \frac{L}{\text{mol"xx1.7824g/L~~39.9258g"/}} m o l$