PSI Barbering Practice Exam

An example of a chemical change is:

1. Evaporation

2. Concentration

3. Reduction

4. Inversion

The correct answer is: Reduction

A chemical change involves a transformation that alters the chemical composition of a substance, resulting in the formation of new substances. Reduction, which refers to the gain of electrons or decrease in oxidation state by a substance during a chemical reaction, exemplifies a chemical change. This process is fundamental in various chemical reactions, particularly in organic chemistry and during redox reactions. In contrast, evaporation, concentration, and inversion do not result in new substances; rather, they represent physical changes. Evaporation is the process where a liquid turns into vapor, concentration refers to the process of increasing the amount of solute in a solution, and inversion often describes the change in the optical activity of substances, which does not involve a chemical alteration of the compounds themselves. Thus, reduction stands out as the only option that represents a true chemical change.