Air at 40C and 2.0 atm is passed through a shallow bed of naphthalene spheres 12 mm in diameter at a rate of 2 m/s, based on the empty cross section of the bed. The vapor pressure of naphthalene is 0.35 mm Hg. How many kilograms per hour of naphthalene will evaporate from 1 m³ of bed, assuming a bed porosity of 40 percent?