Zn + 2HCl - ZnCl2 + H2
Assuming the acid was in excess (so all of the zinc reacts), how many mols of hydrogen would you produce?
You will produce the number of mols H2 that you have mols Zn. You don't have mols Zn anywhere in the problem.
To determine the number of moles of hydrogen produced, we need to use the stoichiometry of the balanced chemical equation.
Let's analyze the balanced equation:
Zn + 2HCl → ZnCl2 + H2
From the equation, we can observe that one mole of zinc reacts with 2 moles of hydrochloric acid (HCl) to produce one mole of zinc chloride (ZnCl2) and one mole of hydrogen gas (H2).
Since the question states that the acid (HCl) is in excess, it means that all of the zinc will react. Therefore, we can assume that the number of moles of zinc (Zn) is equal to the number of moles of hydrogen gas (H2) produced.
Hence, the number of moles of hydrogen gas produced in this reaction would be equal to the number of moles of zinc added.