Athin sheet of naphthalene 0.254 cm thick and 10.2 cm square is place in an air stream parallel to the direction of flow. the air is at 0 °c and 1.0 atm and is moving in laminar flow with a uniform velocity of 15.2 m/s. for how long, in hours, must the sheet be exposed to the air stream before one-quarter of its mass will have sublimed? assume the upper and lower surfaces remain flat at all times. the molecular diffusion coefficient for the air naphthalene system is 185 cm /h and the schmidt number is 2.57 under the conditions given in the problem. the vapor pressure of naphthalene at 0 °c is 0.0059 mmhg. neglect sublimation from the edges. the kinematic viscosity of air can be assumed by be 13.28 x 10 m'/s. the density of naphthalene is 1152 kg/mi