In nanoscale conduction through a very thin gas layer A. The molecules collide more frequently with each other than the solid boundaries. B. The mean free path of the molecules is smaller than the physical dimensions. C. The molecules collide more frequently with the solid boundaries than with each other. D. Both A and B E. Both B and C

Ahe-xe mixture containing a 0.75 mole fraction of helium is used for cooling electronics in an avionics application. at a temperature of 300 k and atmospheric pressure, calculate the mass fraction of helium and the mass density, molar concentration and molecular weight of the mixture. if the cooling capacity is 10 l, what is the mass of the coolant?