Kinematic viscosity, density, refractive index, and electrical conductivity of aqueous solutions of poly(ethylene glycol) and of lithium sulfate were experimentally determined at (278.1, 298.1, 308.1, and 318.1) K. The density and refractive index followed a linear behavior with temperature and solute concentration, but kinematic viscosity and electrical conductivity followed a nonlinear relationship. Models were fitted to the data, which gave good agreement with the experimental data. © 2007 American Chemical Society.