Can the Nature of Reactants Predict Reaction Rates?

[mballaz]

So if a reaction involves Fe²⁺ and the same reaction involves Fe³⁺, which one would occur at a faster rate? I know that the nature of the reactants has to due something with this difference in the rate of the reaction but I'm not sure how to explain it. what about C₂O₄^2- (oxalate) and 2CO₂. Which one would occur faster in a reaction in accordance to the nature of the reactants (how many bonds, and physical state)

Here's my attempt: could I say that a reaction with Fe²⁺ and O₂ would have had less intramolecular bonds and therefore as a result of the nature of the reactants, a reaction including FeO would have occurred faster than a reactant of the molecule iron (III) oxide (Fe₂O₃. for oxalate and 2moles of carbon dioxide, i would just say that the oxalate has a change of 2- therefore it would form a compound whereas carbon dioxide is a stable compund with no charge. As a result, the use of 2CO₂ would provide a faster rate of reaction in accordance to the nature of the substance.

 

[Borek]

I am not aware of any approach that will be general enough to allow make reasonable predictions about kinetics.

It doesn't mean such things doesn't exist - but my guess is that there can be many "small rules", applicable only to some narrow classes of reactions, but no general ones.