AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
Abstract View
Raoult was Right: A Fresh Old Look at Solution Thermodynamics
ANTHONY S. WEXLER, Ahmad Ikram, Simon Clegg, Devis Di Tommaso, Xiangwen Wang, University of California, Davis
Abstract Number: 5 Working Group: Aerosol Chemistry
Abstract In 1887, Raoult published his seminal work on the vapor pressure in mixtures stating that the vapor pressure is proportional to the mole fraction of the solute in solution. For dilute solutions, this relation holds but deviations grow as the solution becomes more concentrated especially in concentrated solutions. In 1908, Callendar proposed a simple and intuitive model of water activity as a function of solution composition and hydration number essentially extending Raoult’s theory to more complex solutions where solute and solvent are associated. In 1973, Stokes and Robinson proposed a step-wide hydration model recognizing that the hydration number must decrease as the water activity decreases.
In this work, we derived analytical expressions for molality and solute activity as a function of water activity from infinitely dilute solutions to supersaturation, conditions that often prevail in atmospheric aerosols. We also derive expressions for the hydration number at infinite dilution that reproduces observations. Molecular dynamics simulations demonstrate the distribution of solute hydration which is also incorporated into the model.