Air at 40oC and 2 atm is passed through a shallow bed of naphthalene spheres 10 mm in diameter at a rate of 2m/s, based on the empty cross section of the bed. The vapor pressure of naphthalene is 117 mmHg. How many kilograms per hour of naphthalene will evaporate from 1m3 of bed, assuming a bed porosity of 40 percent?