A 2.3g sample of MgX is reacted with NaOH. The Mg(OH)2 precipitate had a mass of 1.8g. What is the % of Mg in the original sample?

Answer 1

mols Mg(OH)2 = 1.8 g/molar mass Mg(OH)2 = ??
mols Mg = mols Mg(OH)2 since one Mg atom is in one Mg(OH)2.

g Mg = mols Mg x atomic mass Mg = xx

%Mg = (mass Mg/mass sample)*100 =
(xx g Mg/2.3 g sample)*100 = ??

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