A cylinder contains hydrogen gas at pressure of 249 kPa and temperature $27^{\circ} \mathrm{C}$. Its

Question

A cylinder contains hydrogen gas at pressure of 249 kPa and temperature $27^{\circ} \mathrm{C}$. Its density is ( $R=8.3 \mathrm{~J} \mathrm{~mol}^{-1} \mathrm{~K}^{-1}$ )\

Professor PC Thomas Classes · Answer

(b) : Here, $P=249 \mathrm{kPa}=249 	imes 10^{3} \mathrm{~Pa}$\ $T=27^{\circ} \mathrm{C}=27+273=300 \mathrm{~K}, M=2 \mathrm{Y} 10^{-3} \mathrm{~kg}$\ Equation of state, $P V=n R T$\ or $P M=ho R T \quad\left[\because n=\frac{m}{M}ight]$\ or $ho=\frac{P M}{R T}$\ Substituting the values, 
$ ho=\frac{\left(249 	imes 10^{3}ight)\left(2 	imes 10^{-3}ight)}{8.3 	imes 300}=0.2 \mathrm{~kg} / \mathrm{m}^{3} $