Which of the following describes a chemical reaction where two substances combine to form one compound?

A synthesis reaction is characterized by the process where two or more substances (elements or simpler compounds) combine to form a single, more complex compound. This type of chemical reaction is fundamental in both chemical processes and various applications within cosmetology, such as formulating products that require combining different ingredients to create a desired effect, like hair dyes or skincare items.

During a synthesis reaction, the reactants undergo a transformation where bonds are formed, resulting in the creation of new molecular structures. This principle is essential in cosmetology, as understanding how ingredients interact at a molecular level can help professionals create effective and safe beauty products.

In contrast, decomposition involves breaking down a single compound into two or more simpler substances, while reductive and oxidative reactions focus on the transfer of electrons and changes in oxidation states, which are not directly related to the combination of substances to form a new compound. Understanding these differences highlights the significance of synthesis reactions within the field, particularly in creating comprehensive formulations.