The mass of one mole of atoms of a substance is equal to what?

The mass of one mole of atoms of a substance is equal to the relative atomic mass of the substance expressed in grams. The correct answer reflects a fundamental concept in chemistry where the relative atomic mass is numerically equivalent to the mass of one mole of that element in grams.

For example, if the relative atomic mass of carbon is 12, then one mole of carbon atoms weighs 12 grams. This relationship is a cornerstone of stoichiometry in chemistry, allowing scientists to convert between the number of moles and the mass of a substance in practical applications.

In contrast, the total number of atoms in the substance does not provide a mass measurement, while the relative formula mass typically refers to compounds consisting of more than one type of atom. Molecular weight can be used interchangeably with relative molecular mass in some contexts, but it is generally less precise and is often used for molecular compounds rather than atomic substances. Hence, recognizing the correct relationship between moles, mass, and atomic mass is crucial for understanding many chemical principles.