Gibbs free energy determines whether a reaction will occur spontaneously or not. Still, the activation barrier of a reaction determines if a reaction will occur at a given temperature. At any non-zero temperature every energy level will be populated somehow, but when is population high enough to say that a reaction will take place?
So when is a reaction called feasible at room temperature? A source on this with an energy range for the barrier that can be overcome at a specific temperature (kJ or kcal/mol) so that one considers the reaction actually taking place would be much appreciated.