Consider the vaporization of liquid water to steam at a pressure of 1 atm. (d) At what temperature are the two phases in equilibrium?

Key Concepts

Phase Equilibrium

Phase equilibrium occurs when the rates of the forward and reverse processes of a phase change are equal, resulting in no net change in the amount of each phase. In the context of vaporization, this means that the rate at which water molecules escape from the liquid phase to the gas phase (steam) equals the rate at which gas molecules condense back into the liquid phase.

Vapor Pressure

Vapor pressure is the pressure exerted by a vapor in equilibrium with its liquid at a given temperature. For water, the vapor pressure increases with temperature, and at 1 atm, the temperature at which the vapor pressure of water equals the atmospheric pressure is the boiling point, which is 100°C at standard atmospheric conditions.

Boiling Point

The boiling point of a substance is the temperature at which its vapor pressure equals the external pressure surrounding the liquid. For water at 1 atm, the boiling point is 100°C, which is the temperature at which liquid water and steam can coexist in equilibrium, allowing for the phase transition to occur.