Densities and sound velocities in 0.1 mol.kg(-1), 0.5 mol.kg(-1), and 1.0 mol.kg(-1) sodium carbonate and sodium sulfate solutions were determined at I K temperature intervals in the 278.15 K to 323.15 K range. Measured quantities were expressed as polynomials of temperature, and these polynomials were used to evaluate the apparent molar volumes V-2,V-phi(T,m), the isobaric thermal expansibilities alpha(T,m), the product of temperature and the second-order derivatives of volume with respect to temperature T(partial derivative V-2/partial derivative T-2)(P.m) (changes in isobaric heat capacities with respect to pressure -(partial derivative C-p/partial derivative P)(T.m)), the isentropic compressibilities K-S(T,m), the isothermal compressibilities (KT)(T,m), the apparent molar compressibilities K-2,K-phi(T,m), the isochoric thermal pressure coefficients (partial derivative P/partial derivative T)(V,m), the change of cubic expansion coefficients with pressure at constant temperature and the second-order derivatives of pressure with respect to temperature T(partial derivative P-2/partial derivative T-2)(V,m) (changes in isochoric heat capacities with respect to Volume (partial derivative C-V/partial derivative V)(T,m)).