Justify or criticize the statement that “the activation energy has no net effect on the energy change of a reaction”.

Ineed to find the answer of this question because i dont understand it

4.25g sample of solid ammonium nitrate dissolves in 60.0g of water in a coffee-cup calorimeter, the temperature drops from 22.0 c to 16.9 c. assume that the specific heat of the solution is the same as that of pure water. calculate delta(h) (in kj/mol nh4no3) for the solution proces.

Nuclear decay is the spontaneous decay of one element into a. an x-ray b. a ray of light c. another element