Why does every chemical reaction require a certain amount of activation energy? A. Energy is released when the reactants begin to react

B. Energy loss to the environment during the reaction must be replaced

C. Forming the activated complex requires energy

D. The products have more potential energy than the activated complex

E. The reactants have less potential energy than the products

The content of manganese (mn) in steel was determined spectrophotometrically and with the use of the standard addition method. an unknown sample of mn from a digested steel sample gave an absorbance of 0.185 when analyzed spectrophotometrically. when 5.00 ml of solution containing 95.5 ppm mn was added to 50.0 ml of the unknown steel solution (digested sample), the absorbance was 0.248. calculate the concentration, in parts-per-million (ppm), of mn in the digested steel sample solution.