Washington Esthetician State Board Practice Exam

The correct answer highlights that compounds are specifically formed from two or more different elements that are chemically bonded together. This chemical bonding is what differentiates compounds from mixtures, where the components retain their individual properties and can be separated by physical means.

In a compound, the elements involved undergo a chemical reaction to form new substances with unique properties that are different from those of the individual elements. For example, water (H2O) is a compound made up of hydrogen and oxygen atoms that are chemically bonded, resulting in a substance that has different characteristics than either hydrogen or oxygen alone.

The other options do not accurately define compounds. For instance, while some compounds do exist as solids, they can also be gases or liquids depending on the specific compound and its temperature and pressure conditions. Additionally, compounds can be broken down into their constituent elements through chemical reactions, such as electrolysis with water. Lastly, a compound must consist of multiple types of atoms; if it contains only one type of atom, it is classified as an element, not a compound. Thus, the defining feature of compounds is their composition, consisting of two or more different elements that are chemically bonded together.