no spontaneous process is possible in which heat is
When Î´S is negative and Î´H is negative, the relative magnitudes of Î´S and Î´H determine if the reaction is spontaneous. Low temperatures make the reaction more favorable. When Î´S is negative and Î´H is positive, a process is not spontaneous at any temperature, but the reverse process is spontaneous.A spontaneous process is the time-evolution of a system in which it releases free energy (usually as heat) and moves to a lower, more thermodynamically stable energy state. spontaneous process is capable of proceeding in a given direction, as written or described, without needing to be driven by an outside source of energy.