Question

The density of a gas is found to be $1.56g/L$ at $745$ mm pressure and $65{}^{o}C$. What is the molecular mass of the gas?

• A. $44.2u$
• B. $4.42u$
• C. $2.24u$
• D. $22.4u$

Answer 1

The correct option is A $44.2u$

Pressure is $p=745mm=0.98atm$ (1 atm = 760 mm Hg)

Temperature is $T={65}^{0}C=65+273=338K$

density is $d=1.56g/L$

$P=\frac{dRT}{M}$ where M is molecular wt.

$⟹M=\frac{dRT}{P}⟹M=\frac{1.56\times 338\times 0.0821}{0.98}=44.2u$

Hence, the molecular mass of the gas is $44.2u$.