Question

The average kinetic energy of an ideal gas per molecule in $SI$ units at ${25}^{\circ }C$ will be :

• A. $6.17\times {10}^{-21}kJ$
• B. $6.17\times {10}^{-21}J$
• C. $6.17\times {10}^{-20}J$
• D. $7.16\times {10}^{-20}J$

Answer 1

The correct option is B $6.17\times {10}^{-21}J$

The average kinetic energy of an ideal gas per molecule in $SI$ units at ${25}^{\circ }C$ will be $6.17\times {10}^{-21}J$

The average kinetic energy of an ideal gas per molecule is given by the expression
Average kinetic energy $=\frac{3}{2}kT$

Here, $k$ is boltzmann constant and $T$ is absolute temperature.

$k=1.36\times {10}^{-23}J/K$

$T=25+273=298K$

Average kinetic energy $=\frac{3}{2}\times 1.36\times {10}^{-23}J/K\times 298K=6.17\times {10}^{-21}J$

So, the correct option is $B$