At what point is the vapor pressure of a liquid measured?
A) When molecules escape from the liquid more rapidly than they are recaptured by the liquid.
B) When molecules are recaptured by the liquid more rapidly than they escape from the liquid.
C) When molecules escape and are recaptured at the same rate.
D) When the liquid totally converts to vapor.

Question

Quizplus · Accepted Answer

The vapor pressure of a liquid is measured at the point where the rate of molecules escaping from the liquid phase into the vapor phase is equal to the rate at which molecules are recaptured from the vapor phase back into the liquid phase. This equilibrium state ensures a constant vapor pressure at a given temperature.

At What Point Is the Vapor Pressure of a Liquid