Suppose there are two identical gas cylinders. One contains the monatomic gas krypton (Kr), and the other contains an equal mass of the monatomic gas neon (Ne). The pressures in the cylinders are the same, but the temperatures are different. Determine the ratio KEKr/KENe of the average kinetic energy of an atom of krypton to the average kinetic energy of an atom of neon.

Let equal mass of Ne and Kr be m gm

no of moles of Ne and Kr will be m / 20 and m / 84 (atomic weight of Ne and Kr is 20 and 84)

Let the pressure and volume of both the gases be P and V respectively.

The temperature of Ne be T₁ and temperature of Kr be T₂.

For Ne

PV = (m / 20) x R T₁

For Kr

PV = (m / 84) x R T₂

T₁ / T₂ = 84 / 20

We know that

average KE of an atom of mono atomic gas = 3 / 2 x k T

k is boltzmann constant and T is temperature.

KEKr/KENe = T₂ / T₁

= 20 / 84