Atomic mass unit refers to an atom not a molecule and is based off the carbon 12 isotope. For example uranium has a amu of 235. Molecular mass is grams/mole of a molecule.
I agree with the first two sentences, but I've seen molecular mass expressed in amu as well because it is the sum of component atoms that make up one molecule. One website wrote: "The units are different: *
molecular weight is in atomic
mass units, because it's the
mass of one
molecule. *
molar mass is in grams per mole, because it's the
mass of a mole of
molecules" (Quora.com).
The question I am referring to
gives the mass of one molecule and asks for
molecular mass, but Destroyer multiplied the given mass of the molecule by 6E23--the
molar mass (g/mol) as the correct answer. According to that source I included above, g/mol would be incorrect and the answer would be the mass of the molecule given, as opposed to the solution in the back of the book.
Note: I realize Quora is not a completely reliable source that is one reason why I am posting. I also posted in case other people are confused by this as well.