The thermal conductivity of Kr is roughly half that of Ar under identical pressure and temperature conditions. Both gases are monatomic such that C_V,m = 3/2R.

a. Why would one expect the thermal conductivity of Kr to be less than that of Ar?

b. Determine the ratio of collisional cross sections for Ar relative to Kr assuming identical pressure and temperature conditions.

c. For Kr at 273 K at 1atm,κ = 0.0087 J K ⁻¹ m⁻¹ s⁻¹. Determine the collisional cross section of Kr.