In chemistry, what does the term 'reactants' refer to?

The term 'reactants' specifically refers to the starting materials that participate in a chemical reaction. These are the substances that undergo transformation as the reaction proceeds, resulting in the formation of products. Understanding reactants is essential in the study of chemical reactions, as they determine what substances are available for the reaction to occur.

In the context of a chemical equation, reactants are typically located on the left side, while products, the substances formed as a result of the reaction, are found on the right side. This distinction is fundamental to learning about chemical processes and balancing equations.

The other options mention aspects like products or catalysts, which play different roles in a reaction. Products are the substances produced after the reaction has occurred, while catalysts are agents that speed up the reaction without being consumed in the process. Therefore, only the starting materials that undergo change in a reaction accurately represent what is meant by 'reactants.'