Answer:
Formula mass and molecular mass are calculated separately because they have different meanings and applications in chemistry.
Formula mass is the sum of the atomic masses of all the atoms in a formula unit of an ionic compound. It is used to determine the stoichiometry of a reaction involving ionic compounds, such as in the calculation of limiting reactants or the composition of a sample.
Molecular mass, on the other hand, is the sum of the atomic masses of all the atoms in a molecule of a covalent compound. It is used to determine the molecular weight or molar mass of a substance, which is important for various calculations involving concentrations, such as in the determination of the amount of a substance in a solution.
While the calculation process for both formula mass and molecular mass is the same, the formulas being used are different, and this results in different values for each. Additionally, the concepts of ionic compounds and covalent compounds are different, and they have different chemical properties and behaviors that make it necessary to distinguish between the two types of masses.
Step-by-step explanation:
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