# Why Is A Unimolecular Reaction Analogous to Decay

Hi,

I've noticed that the same method is used to derive both decay rate and the reaction rate for a unimolecular reaction.

The thing I don't understand is, how do we know that the rate of a nuclear reaction is only dependent on k*t

I mean with chemistry, this is something you find out by experiment. what about in nuclear?

## Answers and Replies

Theory is based on assumption that any nucleus decays independently of the others at a random time. That leads to Poisson statistics which provides results such as exponential decay with the half-life rule. All of which can be checked with experiment.

unimolecular reaction and nuclear decay are both under the class of 1st order kinetics. This class is the only one in which the rate does not depend on the inital concentration. For other classes (zero order, 2nd order, ....) the rate depends on the concentration