What is the mass of 3.90 moles of magnesium chloride

find the molar mass of MgCl2 by adding the molar masses of its components then (24.305) + 2 (35.453) = 95.211 MgCl2 then, use stoichiometry to determine the mass of 8.9 moles

First we have to find the Molar Mass of Magnesium Chloride (MgCl2)

Molar mass of

Mg-24.30

Cl-35.45x2 (we do times 2 because there are 2 Cl atoms)

Add the molar masses together, and you get 95.20

One mole=95.205g

And there are 3.90 moles so

95.205*3.90=371.28

3.90moles of MgCl2 = 371.28g