Which property does each equation demonstrate?(3z4 + 2z3) – (2z4 + z3) = z4 + z3

How has the scientific community addressed the safety of chemicals? a. chemicals are repeatedly tested, even those that have existed for a long time. b. existing chemicals are tested if they have never been tested before. c. chemicals are tested if they are suspected to have caused a problem. d. only new chemicals are tested.

An electron moved from shell n = 2 to shell n = 1. what most likely happened during the transition? a fraction of a photon was added. a photon of energy was absorbed. a fraction of a photon was removed. a photon of energy was released.

To find the enthalpy of a reaction in the lab, you measured the of the reactants and the change during the reaction.