Question

A tank used for filling helium balloons has a volume of $0.3{\text{m}}^3$ and contains $2\text{mol}$ of helium gas at ${20}^{\circ }\text{C}$. Assuming that the helium behaves like an ideal gas, find the total translational kinetic energy of the molecules of the gas

• A. $7.3\text{kJ}$
• B. $10\text{kJ}$
• C. $3.65\text{kJ}$
• D. $2.4\text{kJ}$

Answer 1

The correct option is A $7.3\text{kJ}$

Given, $n=2\text{mol},T=273+{20}^{\circ }\text{C}=293\text{K}$
Total translational kinetic energy $(KE{)}_{trans}=\frac{3}{2}nRT$ ($\because$ Helium is monoatomic)
$=\frac{3}{2}\times 2\times 8.31\times 293$
$=7.3\times {10}^3\text{J}$ (or) $7.3\text{kJ}$