Question

What is the average kinetic energy (in kJ mol^-1) of a hypothetical gas with molecular weight 12.8 g mol^-1 at a temperature of 24.7 °C? Do not try to identify the gas.

Answer 1

The average kinetic energy of a gas is determined by the following equation:

$E_T= \frac{3}{2} RT$

where $R$ is the universal gas constant 8.314 $J mol^{-1} K^{-1}$ J mol^-1 K^-1, $T$ is a temperature. The average kinetic energy is:

$E_T= 8.314 \times (24.7+273) K = 3714.5 J/mol =3.71 kJ/mol$