Speed of sound in NaCl, MgCl2, Na2SO4, and MgSO4 aqueous solutions as functions of concentration, temperature, and pressure

The speeds of sound in aqueous solutions of NaCl, MgCl2, Na2SO4, and MgSO4 have been measured relative to pure water from 0 to 1 molal ionic strength, 0° to 55 ° C, and 0 to 1000 bar applied pressure. The 1‐atm results have been fitted to polynomial equations of concentration and temperature with standard deviations of about 0.1 m/s, U0−UW0=am+bm3/2+cm2 where U0 and UW0 are the 1‐atm sound speeds in solution and in pure water, respectively; m is molality; and a,b, and c are temperature‐dependent parameters. The effect of pressure on the relative speeds of sound has been fitted to equations of the form (UP−UWP)−(U0−UW0) =dm+em3/2+fm2, where UP and UWP are the sound speeds of the solution and water at applied pressure P and d,e, and f are temperature‐ and pressure‐dependent parameters. The standard deviations of the least‐squares fits are within 0.12 m/s for all the salts.