Surface Tensions and Densities of Oxalic, Malonic, Succinic, Maleic, Malic, and <i>cis</i>-Pinonic Acids

Abstract

The surface tensions and densities of aqueous solutions of oxalic, malonic, succinic, maleic, malic, and cis-pinonic acids were measured as a function of the acid mole fraction at 25 °C. These organic acids are typically found in atmospheric aerosols. The surface tensions were measured using the Wilhelmy plate method and were measured also as a function of temperature. The measurable mole fractions were limited by the solubilities of the acids at room temperature. All the acids lower the surface tension of pure water. cis-Pinonic acid lowers the surface tension most effectively. The measured surface tensions were fitted with equations covering the acid mole fraction range from zero to one and assuming a theoretical surface tension of pure, supercooled acids at room temperature. The measured densities were also fitted in a similar way. These equations can be used in model calculations of formation and growth of atmospheric particles.