Question

At standard pressure and temperature conditions, calculate the density of a gas whose molecular weight is $45g/mol$.

• A. $2$
• B. $22.4$
• C. $11.2$
• D. $1000$

Answer 1

Answer: (A)

$2$

At STP, T=273.15 K and P = 1 atm

$PV=nRT$ ; $n=\frac{w}{45};d=\frac{w}{V}$

$⟹1atm\times V=\frac{w}{45}\times (0.0821lit.atm.{mol}^{-1}.K^{-1})\times \left(273.15K\right)⟹d=2.006g{cc}^{-1}$