Much can be learned about the molecular properties of liquids and solutions from investigations concerning acoustic velocity and attenuation. However, systematic studies are needed. Sound velocities in aqueous solutions ofLi2SO4, Na2SO4, KHSO4, K2SO4, (NH4)2SO4, andMgSO4were measured over wide ranges of concentration and over the temperature range 0 to 80°C. It was found that the sound velocityversustemperature curves rise and are displaced toward lower temperatures with increase in concentration. Except at concentrations above about one molar the curves are, within the limits of experimental error, the same as the displaced curve for water. The specific acoustic impedance of these sulfate solutions varies linearly with concentration at 20°C. Adiabatic compressibilities are well represented by an empirical expression. Relative association was found to rise with increase in concentration. This is because of solvation of the ions in solution. From the available data apparent molal compressibilities were computed for the temperature range 15 to 35°C.