A student was asked to determine the percentage of the components of a mixture of potassium bromide (KBr), magnesium hydroxide, Mg(OH)2, and barium sulfate (BaSO4).The mass of the sample of the mixture used was 3.21g.
The student extracted the KBr from the mixture with water and filtered insoluble Mg(OH)2 and BaSO4 from the solution, containing the KBr. After evaporating the filtrate, the student recovered and dried the KBr and found it weighed 1.43g.
The student treated the insoluble residue of Mg(OH)2 and BaSO4 with 3M HCL, dissolving the Mg(OH)2 . The student then decanted the supernatant liquid containing aqueous MgCl2 from the insoluble Ba(SO)4. After drying the solid, the student recovered 0.58 g of BaSO4.
The student next added 3M KOH solution to the aqueous solution and Mg(OH)2 precipitated. After filtering the solution and drying the precipitate, the student recovered 1.10g of Mg(OH)2.
1. Calculate the percent Mg(OH)2 in the mixture?