A puddle of water \(1 \mathrm{~m}\) in diameter and \(1 \mathrm{~cm}\) deep sits on your driveway. The air temperature is \(20^{\circ} \mathrm{C}\) and a slight breeze is blowing at \(4 \mathrm{~m} / \mathrm{s}\). The relative humidity is a comfortable \(35 \%\). You may assume the water is at the same temperature as the air and the puddle diameter remains constant as the water evaporates.

a. What is the driving force for mass transfer?

b. What is the mass transfer coefficient?

c. Under these conditions, how long will it take for the puddle to disappear?