Consider a two-phase, liquid-vapor equilibrium. In this case, we will assume that the liquid is a spherical droplet with volume V, surface area A, and radius r. We have an isolated system (there is no gravity): The vapor phase can be described as in class, but since the droplet has surface tension, there is an additional work term: The vapor phase can be described as in class, but since the droplet has surface tension, there is an additional work term: