Consider a hemispherical droplet of liquid water residing on a flat surface. Still air surrounds the droplet. At an infinitely long distance from the gas film, the concentration of water vapor in the air is effectively zero. At a constant temperature of 30 oC and 1 atm total pressure, the evaporation rate of the droplet is controlled by the rate of molecular diffusion through the still air. Determine the time it will take for the water droplet to completely evaporate at 30 oC and 1 atm total system pressure if the initial droplet radius is 5 mm. The vapor pressure of water at 30 oC is 31.824 mmHg. The diffusivity of water vapor in air is 0.260 cm2/s at 25 oC and 1 atm.