Two moles of an unknown substance were shown to have a mass of 240g. what molecular mass does the substance have?

Molecular mass or molecular weight is the mass of a molecule. It is calculated as the sum of the atomic weights of each constituent element multiplied by the number of atoms of that element in the molecular formula. So if there are 2 moles, then it is multiplied to 240 g, which will result to 480 g -- the molecular mass of the substance.

Just took the quiz on edgenuity and the correct answer is "c.  4.54 x  10–12  j"