Related Experiment Video
Updated: Aug 24, 2025

High-pressure Sapphire Cell for Phase Equilibria Measurements of CO2/Organic/Water Systems
Published on: January 24, 2014
Experiments on Vapor Pressure of KCl at Different Molar Fractions in Mixtures of KCl + K2SO4
Xiuhua Li1, Fang He2, Frank Behrendt3
1Shandong Vocational College of Science and Technology, Weifang, Shandong261053, China.
Abstract:
The objective of this paper is to measure the vapor pressure of potassium chloride (KCl) in its mixture with potassium sulfate (K2SO4). Evaporation behavior of pure salts of KCl, K2SO4, and their mixtures at different molar fractions were examined using a simultaneous thermogravimetric analyzer (STA) at different temperatures with a pair of crucibles (outer: platinum; inner: alumina). The dependence of the vapor pressure of KCl on its molar fraction in mixtures of KCl + K2SO4 was obtained on the basis of relative pressure. Results show that vapor pressure of KCl is increased to 1.2 times when a small amount of K2SO4 (molar fraction from 0.05 to 0.20) is added. Evaporation of KCl will be inhibited by K2SO4 when the molar fraction of K2SO4 is higher than 0.27, which is its fraction in the eutectic system of KCl + K2SO4. Vapor pressure of KCl decreases significantly with increasing molar fractions of K2SO4 at its inhibition scope.
Related Concept Videos
Clausius-Clapeyron Equation
Vapor Pressure Lowering
Dissolving a nonvolatile substance in volatile liquid results in a lowering of the liquid’s vapor pressure. This phenomenon can be explained by considering the effect of added solute molecules on the liquid's vaporization and condensation processes. To vaporize, solvent molecules must be present at the surface of the solution....
Solubility Equilibria
The...
Vapor Pressure
Homogeneous Equilibria for Gaseous Reactions
For gas-phase reactions, the equilibrium constant may be expressed in terms of either the molar concentrations (Kc) or partial pressures (Kp) of the reactants and products. A relation between these two K values may be simply derived from the ideal gas equation and the definition of molarity. According to the ideal gas equation:
Vapor Pressure of Fluid
When a liquid is placed in a closed container with a small air space, and the space is evacuated, vapor molecules will...

