[en] We consider the generalization of the kinematic apse to nonreactive polyatom--polyatom impulsive collisions, dissociative atom--molecule impulsive collisions, and (partially) impulsive reactive atom--diatom collisions. Appropriate generalizations of the kinematic apse are obtained along which there is a classical propensity for preserving the projection of the total intrinsic spin. In the case of reactive scattering, we discuss several different situations for which such a propensity occurs. For reactive systems in which no such propensity exists, the analysis may still provide a basis for classifying reactions