The magnesium is used in the airplane bodies and the other type of lightweight alloys. Thus the metal is obtained from the seawater in a procedure that involves the neutralization, precipitation, electrolysis and the evaporation. Determine the number of kilograms of Mg can be obtained from 1 km^3 of seawater if the initial Mg]2+ concentration is 0.13 % by the mass and density of the seawater is 1.04 g/mL?