Study of the Thermodynamics (Thermal and Cl Catalyzed) and Kinetics of the Cis and Trans Isomerizations of CF3CF═CHF, CF3CH═CHCF3, and CH3CH═CHCH3 in 100–950 Torr of N2 Diluent at 296–875 K: Effect of F and CF3 Substitution on the Isomerization Process Including the Fluorine “Cis Effect”