When you use 55mL of 4.0 M hydrochloric acid how many grams of zinc do you need to react with it?

Answer 1

The balanced equation for the reaction of zinc with hydrochloric acid is ...

Zn(s) + 2HCl(aq) ==> ZnCl₂(aq) + H₂(g)

mols HCl present = 55 ml x 1 L / 1000 ml 4.0 mol / L = 0.22 mols HCl

mols Zn needed = 0.22 mols HCl x 1 mol Zn / 2 mols HCl = 0.11 mols Zn

atomic mass of Zn = 65.4 g/ mol

mass of Zn needed = 0.11 mols Zn x 65.4 g / mol = 7.2 g Zn (2 sig. figs.)