Question

If the density of a helium gas is $0.1{\text{kg m}}^{-3}$ at pressure $249\text{kPa}$, then temperature of the gas will be nearly $[R=\frac{25}{3}{\text{J mol}}^{-1}{\text{K}}^{-1}]$

• A. ${1195}^{\circ }\text{C}$
• B. ${922}^{\circ }\text{C}$
• C. ${27}^{\circ }\text{C}$
• D. ${327}^{\circ }\text{C}$

Answer 1

The correct option is B ${922}^{\circ }\text{C}$

By ideal gas equation
$PV=nRT$
$P=\frac{\rho }{M}RT$
$\Rightarrow T=\frac{PM}{\rho R}$
$\Rightarrow T=\frac{249\times {10}^3\times 4\times {10}^{-3}}{0.1\times \frac{25}{3}}$
$\Rightarrow T=1195\text{K}.$
$\Rightarrow t=1195-273={922}^{\circ }\text{C}$