PSI Barbering Practice Exam 2026 - Free Barbering Practice Questions and Study Guide

A chemical reaction is characterized by the breaking and forming of chemical bonds, which leads to the transformation of reactants into products. In such reactions, the arrangement of atoms changes, resulting in the creation of new substances with different properties from those of the original reactants. This process may involve either the release or absorption of energy, but the essential feature defining a chemical reaction is the change in the chemical structure of the substances involved.

Physical reactions, in contrast, involve changes in the physical state or appearance of a substance without altering its chemical composition. Endothermic and exothermic reactions are specific types of chemical reactions that describe whether energy is absorbed or released, respectively. However, they do not encapsulate the broader definition of a chemical reaction, which is primarily focused on the breaking and forming of bonds.