Question

Magnesium reacts with hydrochloric acid, HCl, to form magnesium chloride and hydrogen gas. The reaction is: Mg + 2HCl → MgCl2 + H2 What is the mass of HCl that would be required to completely react with 5.2 grams of Mg? 6.9 6.934 16 15.60

Answer 1

Answer is: mass of HCl is 15,6 g.
Chemical reaction: Mg + 2HCl → MgCl₂ + H₂.
m(Mg) = 5,2 g.
n(Mg) = m(Mg) ÷ M(Mg).
n(Mg) = 5,2 g ÷ 24,3 g/mol.
n(Mg) = 0,213 mol.
From chemical reaction: n(Mg) : n(HCl) = 1 : 2.
n(HCl) = 0,426 mol.
m(HCl) = 0,426 mol · 36,45 g/mol.
m(HCl) = 15,6 g.