What is the mass of 647 moles of Al2 SO4 3?

A properly written formula for the compound, using the subscript fonts available for answers but not for questions, is Al2(SO4)3. This formula shows that there are 2 aluminum atoms, three sulfur atoms, and twelve oxygen atoms in each formula unit, for a total of 342.14 grams per formula unit. 647 of these formula units will have a mass of 647 X 342.14 gramsor 221 kilograms, to the justified number of significant digits.