Question

Calculate the weight of $O_2\left(g\right)$ necessary to fill up a cylinder of 5 $\text{L}$ capacity at $27°C$ and 100 $\text{atm}$ pressure, when the compressibility factor is 0.96.
(Take $R=\frac{1}{12}{\text{L atm mol}}^{-1}{\text{K}}^{-1}$)

• A. $133.3\text{g}$
• B. $640\text{g}$
• C. $614.4\text{g}$
• D. $666.7\text{g}$

Answer 1

The correct option is D $666.7\text{g}$

$pV=nZRT$
We can calculate $n$ and hence the mass needed.
$n=\frac{pV}{ZRT}=\frac{100\times 5}{0.96\times 1/12\times 300}=\frac{125}{6}\text{mol}$
mass $=32n=\frac{125}{6}\times 32=666.67\text{g}$