Relative sound velocities of sea salts at 25°C

Abstract

The relative sound velocities (u−u0) of aqueous HCL, LiCL, NaF, NaCL, NaBr, NaI, NaNO3, NaOH, NaHCO3, Na2SO4, KF, KCL, KBr, KI, KNO3, K2CO3, K2SO4, RbCl, CsCl, NH4Cl, NH4Br, MgCl2, CaCl2, SrCl2, BaCl2 and MgSO4 solutions were measured from 0.01 to 1.0 at 25°C. The sound velocities were fitted to a function of molality (maximum standard deviation 0.05 m sec−1) u=u0+Am+Bm(3/2)+Cm2, where u0 is the sound velocity in pure water, and A, B, and C are temperature dependent parameters. The adiabatic compressibilities βS were determined from the sound velocities and were used to calculate the adiabatic apparent molal compressibilities φK(S) of the salts. The φK and βS of seawater were estimated by using Young’s rule. The calculated values of φK and βS agree with those determined from the measurements on seawater solution to ±0.18×10−4cm3mol−1bar−1 and ±0.004×10−6bar−1. The sound speeds of seawater calculated from the values of βS estimated from Young’s rule agree on the average to ±0.02m sec−1 (maximum standard deviations 0.07 m sec−1) with the direct measurements of Millero and Kubinski.