Which statement best describes the relationship between an element's molar mass and its atomic mass?

• A. The molar mass of an element in grams per mole is numerically equal to its atomic mass in atomic mass units (u).
• B. The molar mass of an element is unrelated to its atomic mass.
• C. The molar mass of an element is always twice its atomic mass.
• D. The molar mass of an element is the atomic mass divided by Avogadro's number.

Answer: (A)

Verified step by step guidance

1. Understand that atomic mass is the mass of a single atom of an element, usually expressed in atomic mass units (u), where 1 u is defined relative to the carbon-12 isotope.
2. Recognize that molar mass is the mass of one mole of atoms of an element, expressed in grams per mole (g/mol). One mole contains Avogadro's number (\$6.022 \times 10^{23}$) of atoms.
3. Recall that the atomic mass in atomic mass units (u) and the molar mass in grams per mole (g/mol) are numerically equal because the mole bridges the microscopic scale (atoms) to the macroscopic scale (grams).
4. Note that the molar mass is not twice the atomic mass, nor is it unrelated; it is also not the atomic mass divided by Avogadro's number, since dividing by Avogadro's number would give the mass of a single atom in grams, which is extremely small.
5. Conclude that the correct relationship is: the molar mass of an element in grams per mole is numerically equal to its atomic mass in atomic mass units (u).