The mass of a quantity of NiCl2 is 24.6 g. How many formula units are in the sample?

Question

A. 3.2 3 1023 NiCl2 formula units
B. 5.3 3 10–21 NiCl2 formula units
C. 1.1 3 1023 NiCl2 formula units
D. 1.9 3 1027 NiCl2 formula units

Answer 1

mols = grams/molar mass
In this case formula unit is that for NiCl2 in what I've called molar mass above. In this case, mols = formula units.