21. Chemical Reactions. a) A unimolecular reaction occurs when a molecule rearranged itself into a product of one of more different products. For example, the parent nucleus of uranium-238 decays to a daughter nucleus of thorium-234 (and in turn emits an alpha particle.) We Can denote the unimolecular reaction by A->B The rate law for this reaction can be determined by noting that the disappearance of reactant A is equal to the rate of formation of product B, both of which are proportional to the concentration of A. Write down the rate equations that governs the disappearance of A and the formation of product B