The reaction of hyperthermal (0.1 eV --> 2.6 eV) CO2 with Si(100)2 x 1 at less than or equal to 300 K has been studied with high-resolution electron energy loss spectroscopy (HREELS), low energy electron reflectivity (LEER), temperature programmed desorption (TPD), and Auger electron spectroscopy (AES). The initial sticking coefficient depends on the total kinetic energy of the incident molecule, but is insensitive to the vibrational state. Adsorption results in a dramatic reduction in specular electron reflectivity which is reversed upon desorption of one of the dissociatively adsorbed products, CO, at 400 K. The adsorbed oxygen remains on the surface after annealing to as high as 900 K. Continued exposure results in the population of a CO state which desorbs near 330 K as well as a molecular CO2 state desorbing at 110 K.