For a covalent compound, what other name may the formula mass correctly be given?
- It may also be called the percent composition
- It may also be called the molecular mass
- It may also be called the empirical formula
- It may also be called the molar concentration
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Correct answer: B. It may also be called the molecular mass
1. For a covalent substance the formula gives the numbers and types of atoms in one single molecule.
2. Because that formula describes a real molecule, its formula mass may correctly be called the molecular mass.
3. Percent composition is a set of mass percentages, not a mass, so it is a different quantity altogether.
4. Molar concentration measures solute per litre of solution and has nothing to do with a single molecule.
_Source: OpenStax Chemistry (CC BY 4.0), Ch 3 "Composition of Substances and Solutions", section 3.1 Formula Mass and the Mole Concept_