Doubts about kinetics

TenSaru SG

1) Is the k value for the overall reaction related/equal to the k for the reaction with respect to a reactant?

2) Does collision theory apply for decomposition?

3) Why is Kc = k_f / k_b? Isn't k independent of the stoichiometry of reaction?

Thanks a lot :)

UltimaOnline SG

1) Mathematically related. See : http://en.wikipedia.org/wiki/Rate_law

2) Even though the reactant might be unimolecular, bear in mind the polymolecular products exist in equilibrium with the reactant.

3) k is related to the orders with respect to each reactant, which is in turn related to the stoichiometry of the elementary rate determining reaction. Conceptually, whether the position of equilibrium (indicated by Kc) lies more towards the left or right, and by how much, depends on whether the forward reaction or backward reaction is faster (ie. kf versus kb), and by how much. Hence, Kc = kf/kb.