chemistry %yield

Question

Magnesium is obtained from sea water. Ca(OH)₂ is added to sea water to precipitate Mg(OH)₂. The precipitate is filtered and reacted with HCl to produce MgCl₂. The MgCl₂ is electrolyzed to produce Mg and Cl₂. If 186.0 g of magnesium are recovered from 1000. g MgCl₂, what is the percentage yield for this reaction?

Answer 1

1000. g MgCl2 x 1 mole MgCl2/95.211 g = 10.503 moles MgCl2

Moles of Mg present = 10.503 moles MgCl2 x 1 mole Mg/1 mole MgCl2 = 10.503 moles Mg present

Mass of Mg present = 10.503 moles Mg x 24.305 g/mole = 255.3 g Mg = theoretical yield

% yield = actual yield/theoretical yield (x100%) = 186.0 g/255.3 g (x100%) = 72.86% yield