Question

What is the mass of 3.00 moles of magnesium chloride, MgCl2? Express your answer with the appropriate units.

Answer 1

To answer this question you need to know how to calculate the molecular weight of a molecule. The compound is having 1 Mg atom and 2 Cl atom, thus the molecular weight should be: 
24.305+ 2*35.453= 95.211 gram/mol.

Then, the mass of 3 mol of MgCl would be:
3 mol * 95.211 gram/mol= 285.633 gram