1) Recognize the balanced equation is:
2HCl + Mg(OH)2 = MgCl2 + 2HOH
2) Find moles of HCl
(0.05moles/1L)(.200L) = .01 moles HCl
3) Use conversions to find moles of Mg(OH)2.
(.01mol HCl * 1mol Mg(OH)2)/ 2mol HCl =.005 mol Mg(OH)2
4) .005 * 58.32 (the molar mass) = .2916g Correct sig figs = 0.29g Mg(OH)2
