The sum of the atomic weights of the elements making up a compound is known as the...

The sum of the atomic weights of the elements making up a compound is accurately referred to as molecular weight. This term specifically describes the mass of a single molecule of a substance, calculated by adding the atomic weights of all the atoms in the chemical formula of the compound.

In a molecular context, each element's atomic weight is determined from the periodic table, and these values are summed based on the compound's molecular formula. This calculation is crucial for various applications in chemistry, including stoichiometry, which involves converting between grams and moles during chemical reactions.

While the term "formula weight" is closely related and often used interchangeably with molecular weight in different contexts, molecular weight is the more precise term when referring explicitly to substances at the molecular level. Other options such as "compound weight" and "gross weight" do not accurately capture this definition within standard chemical terminology.