A 1-m square thin plate of solid naphthalene is oriented parallel to a stream of air flowing at 20 m/s. The air is at 310 K and 1:013 × 105 Pa. The naphthalene remains at 290 K; at this temperature, the diffusivity of naphthalene in air is 5:61 ×10-6 m2/s and its vapor pressure is 26 Pa. Determine
a. the value of the mass-transfer coefficient at a point 0.3 m downstream from the leading edge.
b. the moles of naphthalene per hour lost from the section of the plate 0.5-0.75 m downstream from the leading edge.