I calculated some gibbs free energy values for a chemical reaction at 298K and 1773K both giving me negative values . the amount for the reaction at 298K is -162443J and the one at 1773K is -81147.85J. Both shows that the reaction are spontaneous and so thermodynamically the process at 298K is favorable right? If so, why would someone still want the reaction to occur at 1773K? the process is an exothermic reaction.