Zinc metal reacts with hydrochloric acid, HCl (aq), react to give hydrogen gas, H2 (g) and aqueous zinc chloride, ZnCl^2 (aq). A 0.4000 g sample of impure zinc fully reacts completely when added to 750.0 L of 0.0179 M HCl. After the reaction, the molarity of the solution has been reduced to 0.00403 M. What is the percent by mass of zinc in the sample?