Solubilities of N2O in and densities and viscosities of aqueous solutions of ammonia, piperazine (PZ), and their aqueous blends were measured at (283.15, 293.15, 303.15, 313.15, and 323.15) K. The experiments cover the mass fraction ranges: (1 to 30) mol % ammonia, (0.1 to 2) mol % PZ, and (1 to 11) mol % ammonia + (0.18 to 2) mol % PZ in the blended solutions. The results are compared with available data in the literature. The experimental density and viscosity data were correlated using two semiempirical correlations as a function of temperature and concentration of ammonia and PZ.