Chemistry: According to the following reaction, how many grams of hydrochloric acid are required for the complete reaction of 28.7 grams of iron?

Question

iron (s) + hydrochloric acid (aq) —> iron (II) chloride (aq) + hydrogen (g)

Mass= g

Answer 1

This question is only slightly different because they give you grams instead of moles of iron. So, we will convert grams of iron to moles of iron, and then proceed as before.

iron(s) = Fe(s)

hydrochloric acid (aq) = HCl(aq)

iron(II) chloride(aq) = FeCl₂(aq)

hydrogen(g) = H₂(g)

Fe(s) + 2HCl(aq) ==> FeCl₂(aq) + H₂(g) .. balanced equation

atomic mass of Fe = 55.85 g / mol

moles of Fe used = 28.7 g Fe x 1 mol Fe / 55.85 g = 0.514 moles Fe

Stoichiometry: 1 mole Fe = 2 moles HCl

moles HCl required = 0.514 moles Fe x 2 mols HCl / 1 mole Fe = 1.028 moles HCl

grams HCl required = 1.028 moles HCl x 36.5 g HCl/ mole HCl = 37.5 g HCl required