Bromine has two naturally occurring isotopes. Bromine-81 has a mass of 80.916 amu and an abundance of 49.31%. Bromine-79 has a mass of 78.920. What is the abundance of Bromine-79

a. energy is absorbed in the reaction.

if in a given reaction the energy of products is greater than the energy of reactants it means that reaction is endothermic and during the reaction, the energy is absorbed by reactants. in an endothermic reaction, the products have more stored chemical energy than the reactants. and in this reaction the reactants are more stable than products before the compounds with less energy are always more stable.