What is the term for a method of expressing the makeup of a substance that identifies each element and its quantity?

The correct term for expressing the makeup of a substance by identifying each element and its quantity is a chemical formula. A chemical formula provides a concise way to represent the composition of a compound, indicating the elements present and the number of atoms of each element in a molecule. For example, in the formula H₂O, it is clear that there are two hydrogen atoms and one oxygen atom, which defines the composition of water.

Chemical equations describe the reactions between substances but do not provide the makeup of a single substance. Mixture composition refers to the combination of different substances, which may not be represented by a single formula, and elemental analysis involves determining the elemental composition of a substance rather than explicitly stating it in a formula format. Therefore, a chemical formula is the most accurate and specific method of conveying the identity and quantity of elements in a substance.