Q. The pressure in a liquid droplet of radius r is greater than the pressure of the surrounding equilibrated gas phase by a quantity 2 =r, where is the surface tension.

(a) Consider a droplet of water of radius 1.00 x 10^-6 m at 25⁰C suspended in air of the same temperature. The surface tension of water at this temperature is 0.07199 Jm^-2. Find the pressure in the droplet if the pressure of the surrounding air is 1.00 bar.

(b) Calculate the difference between the fugacity of H₂O in the air of pressure 1.00 bar equilibrated with this water droplet, and the fugacity in air equilibrated at the same temperature and pressure with a pool of liquid water having a flat surface. Liquid water at 25⁰C and 1 bar has a vapor pressure of 0.032 bar and a molar volume of 1.807 x 10^-5 m³mol^-1.