calculate the amount of H2 formed?

Question

1.6 mol Zn and 7.6 mol HCl react according to the equation Zn + 2 HCl −→ ZnCl2 + H2 . If the limiting reactant is Zn, calculate the amount of ZnCl2 formed. Answer in units of mol.

Calculate the amount of H2 formed.

Answer 1

Zn + 2HCl ==> ZnCl₂ + H₂ .. balanced equation

Since we are given the moles of BOTH reactants, we must first determine which reactant, if any, is limiting. An easy way to do this is to simply divided moles of each reactant by the corresponding coefficient in the balanced equation. Whichever value is less represents the limiting reactant.

For Zn: 1.6 mol Zn ÷ 1 -> 1.6

For HCl: 7.6 mol HCl ÷ 2->3.8

Since 1.6 is less than 3.8, Zn is the limiting reactant.

Now use the moles of Zn and the stoichiometry of the balanced equation to find moles of product formed:

1.6 mols Zn x 1 mol ZnCl₂ / mol Zn = 1.6 moles ZnCl₂ formed

1.6 mols Zn x 1 mol H₂ / mol Zn = 1.6 moles H₂ formed