How much of a 24-gram sample of Radium-226 will remain unchanged at the end of three half-life periods?

the movie was based there, and all the animals and characters are native.

~courtney

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.