Question

The density of a gas at STP is $1.5$g/L at STP. Its molecular weight is:

• A. $22.4$
• B. $33.6$
• C. $3.36$
• D. $44.8$

Answer 1

Answer: (B)

$33.6$

The condition at STP are:

$P=1atm$

$T=273.15K$

$R=0.0821Latmmo{l}^{-1}{K}^{-1}$

Using the equation, $\rho =\frac{PM}{RT}$

$\Rightarrow M=\frac{\rho RT}{P}$

$\Rightarrow M=\frac{1.5\times 0.0821\times 273.15}{1}$

$\Rightarrow M=33.6g$