Final answer:
One atomic mass unit (amu) is defined as 1.660539 × 10^-24 grams, a standardized value based on the mass of a carbon-12 atom.
Step-by-step explanation:
The question asks about the mass in grams of one atomic mass unit (amu) of a material. By definition, the atomic mass unit (amu) is one-twelfth the mass of a carbon-12 atom. One amu is exactly 1.660539 × 10-24 grams. This means that every amu corresponds to that specific mass in grams, regardless of the material. The atomic masses of elements and the formula masses of compounds are relative to the carbon-12 isotope and are expressed in amu when referring to single atoms or molecules.