Computer simulations were performed to obtain the radial distribution function for two-dimensional Lennard-Jones fluids over a wide range of densities and temperatures and for different contributions of the attractive forces. The repulsive and attractive intermolecular forces are separated following the Weeks-Chandler-Andersen perturbation theory. The influence of the attractive forces on the potential and internal energies, pressure, Helmholtz free energy and chemical potential was then analysed. These results will be used in later studies of the influence of these forces on the vapour-liquid and solid-liquid coexistence curves, and on theoretical adsorption isotherms.