Which of the following statements correctly describes the mass of exactly 1 mole of an element?

• A. It is the same for all elements regardless of their atomic mass.
• B. It is always 12 grams for any element.
• C. It is equal to the element's atomic mass expressed in grams.
• D. It is equal to Avogadro's number expressed in grams.

Answer: (C)

Verified step by step guidance

1. Understand the concept of a mole: A mole is a quantity that contains exactly \$6.022 \times 10^{23}$ entities (Avogadro's number) of a substance, whether atoms, molecules, or ions.
2. Recall the definition of atomic mass: The atomic mass of an element is the average mass of one atom of that element, usually expressed in atomic mass units (amu).
3. Connect moles to mass: The mass of 1 mole of an element in grams is numerically equal to the atomic mass of that element in amu. This means if an element has an atomic mass of \(X\) amu, then 1 mole of that element weighs \(X\) grams.
4. Evaluate the given options: The mass of 1 mole is not the same for all elements because atomic masses differ; it is not always 12 grams (that is specific to carbon-12); and Avogadro's number is a count, not a mass, so it cannot be expressed in grams.
5. Conclude that the correct statement is: The mass of exactly 1 mole of an element is equal to the element's atomic mass expressed in grams.