【Daily Question】Question from Issue 20151030

A、------------------------------------------------------------

The physical meaning of the gas-liquid phase equilibrium constant Ki is (a) A. Under certain conditions, at gas-liquid equilibrium, the ratio of the mass concentration of component i in the gas phase to that in the liquid phase； B. Under certain conditions, at gas-liquid equilibrium, the ratio of the volumetric concentration of component i in the gas phase to that in the liquid phase in the system ； C. Under certain conditions, at gas-liquid equilibrium, the ratio of the percentage concentrations of component i in the gas phase to that in the liquid phase within the system ； D, under certain conditions, at gas-liquid equilibrium, is the ratio of the molecular concentrations of component i in the gas phase to those in the liquid phase.

The physical meaning of the gas-liquid phase equilibrium constant Ki is (D). A. Under certain conditions, at gas-liquid equilibrium, it represents the ratio of the mass concentration of component i in the gas phase to that in the liquid phase； B. Under certain conditions, at gas-liquid equilibrium, the ratio of the volumetric concentration of component i in the gas phase to that in the liquid phase in the system ； C. Under certain conditions, at gas-liquid equilibrium, the ratio of the percentage concentrations of component i in the gas phase to that in the liquid phase within the system ； D, under certain conditions, at gas-liquid equilibrium, is the ratio of the molecular concentrations of component i in the gas phase to those in the liquid phase.

The gas-liquid phase equilibrium constant Ki refers to, at the temperature and pressure conditions of the system when the gas and liquid phases are in equilibrium, the ratio of the molar fraction yi of a certain component i in the gas phase to its molar fraction * in the liquid phase. That is: Ki=yi/* The phase equilibrium constant is the most important parameter in the calculations related to phase equilibrium during the petroleum distillation process. For ideal solutions at pressures below 0.3 Mpa, the phase equilibrium constant can be calculated using the following formula: Ki=Poi/P, where Poi is the saturated vapor pressure of component i at the system temperature, in Pa ； P — System pressure, Pa. For petroleum or its fractions, it is possible to separate them into what can be considered individual components – pseudo-components – using the method of distillation at the actual boiling point. The gas-liquid phase equilibrium during petroleum distillation can then be calculated by employing methods for determining gas-liquid phase equilibrium in multicomponent systems.

The physical meaning of the gas-liquid phase equilibrium constant Ki is (a) A. Under certain conditions, at gas-liquid equilibrium, the ratio of the mass concentration of component i in the gas phase to that in the liquid phase； B. Under certain conditions, at gas-liquid equilibrium, the ratio of the volumetric concentration of component i in the gas phase to that in the liquid phase in the system ； C. Under certain conditions, at gas-liquid equilibrium, the ratio of the percentage concentrations of component i in the gas phase to that in the liquid phase within the system ； D, under certain conditions, at gas-liquid equilibrium, is the ratio of the molecular concentrations of component i in the gas phase to those in the liquid phase.

The correct answer is,,,,,, namely D, the ratio of molecular concentrations

I think it’s moles per... The unit conversion is a bit confusing; let’s go with D, just to participate.

The physical meaning of the gas-liquid phase equilibrium constant Ki is (A)

D, under certain conditions, at gas-liquid equilibrium, is the ratio of the molecular concentrations of component i in the gas phase to those in the liquid phase.

B.......................