Question

How many formula units are in 25.4 g of MgCl2?

Answer 1

Answer: 1.58 x $10^{23}$

Explanation:

1 mole of magnesium chloride has a mass of 95.211 g and contains 6.022⋅$10^{23}$formula units of magnesium chloride, you can say that,

25.0 g x (6.022 x $10^{23}$ form units MgCl2) /95.211 = 1.58 x $10^{23}$