A 0.202 g sample of an Al?Ca alloy reacts with an excess of HCl(aq) to produce 0.0179 g H2(g). What is the mass percent of Ca in the alloy? The unbalanced equations are given below. (Hint: Let x = mass of Ca in the alloy in grams. Question 115 in your textbook is similar.)
Al(s) + HCl(aq) ? AlCl3(aq) + H2(g) Ca(s) + HCl(aq) ? CaCl2(aq) + H2(g)