posted by angel .
What is the mass of 7080 moles of magnesium chloride (MgCl2)?
Do you know the mass of one (1) mole of MgCl2? That is 24.3 + 3*35.44 (approximately but you need to do it exactly). So 2 moles would be twice that, 3 moles would be 3x that, and 7080 moles would be -------that.