Calculate the mass transfer coefficient (kc) when a sphere of naphthalene exposes to air at 45 and 1 atm pressure and flowing at a velocity of 0.416 m/sec. The diameter of the sphere is 23.7 mm. The diffusivity of naphthalene in air at 45 is 6.9210-6 m2/sec and the vapor pressure of solid naphthalene is 0.555 mmHg. The mass transfer coefficient may be obtained from the following correlation:

Sh = 2+ 0.552(Re)0.53(Sc)0.33

Data given- air=1.9310-5 Pa.sec, air=1.113 kg/m3.