magnesium metal (1.00 mol) and a volume of aqueous hydrochloric acid that contains .500 mol of HCL are combined and react to completion. how many liters of hydrogen gas, measured at STP, are produced?

Question

Mg(s) + 2HCL(aq) -> MgCl2(aq) + H2(g)

Answer 1

This is a limiting regent (LR) problem because amounts are given for BOTH reactants.

Mg + 2HCl ==> MgCl2 + H2
mols Mg = 1.00 mol
mol HCl = 0.5M

mols H2 produced from 1. mol Mg + 1 mol
mols H2 produced from 0.5 mol HCl = 1 mol
So this isn't a LR problem after all but the reactants just match. So 1 mol H2 is produced and at STP 1 mol occupies 22.4 L.