(a) Magnesium is obtained from seawater. If the concentration of Mg²⁺ in seawater is 0.050 M, what volume of seawater (in liters) must be treated to obtain 1.00 kg of magnesium metal? What mass of lime (CaO; in kilograms) must be used to precipitate the magnesium in this volume of seawater?
(b) When 1.2 × 10³ kg of molten MgCl₂ is electrolyzed to produce magnesium, what mass (in kilograms) of metal is produced at the cathode? What is produced at the anode? What is the mass of this product? What is the total number of Faradays of electricity used in the process?
(c) One industrial process has an energy consumption of 18.5 kWh/kg of Mg. How many joules are required per mole (1 kWh = 1 kilowatt-hour = 3.6 × 10⁶ J)? How does this energy compare with the energy of the following process? 

MgCl₂(s) → Mg(s) + Cl₂(g)