From Eq. (7.34), a drop of liquid of radius r is at a higher pressure than the vapor it is...

From Eq. (7.34), a drop of liquid of radius r is at a higher pressure than the vapor it is in equilibrium with. This increased pressure affects the chemical potential of the liquid and raises its vapor pressure slightly, (a) Use the integrated form of Eq. (7.38) in Prob. 7.66 to show that the vapor pressure Pr of such a drop is

whereVm,l is the molar volume of the liquid and P its bulk vapor pressure. This is the Kelvin equation. (b) The vapor pressure and surface tension of water at 20°C are 17.535 torr and 73 dyn/cm. Calculate the 20°C vapor pressure of a drop of water of radius 1.00 × 10‒5 cm.