Calculated the amount of substance and the mass of hydrochloric acid required for interaction with magnesium weighing 9.6 g.

Calculated the amount of substance and the mass of hydrochloric acid required for interaction with magnesium weighing 9.6 g. what amount of substance and mass of hydrogen is formed in this case?

Let’s write the reaction equation:
Mg + 2HCl = MgCl2 + H2 ↑.
From the reaction equation:
ν (Mg) = ν (HCl) / 2.
m (Mg) / M (Mg) = m (HCl) / (2 * M (HCl)).
m (HCl) = m (Mg) * (2 * M (HCl)) / M (Mg).
Let’s define the molar masses:
M (Mg) = 24 g / mol.
M (HCl) = 1 + 35.5 = 36.5 g / mol.
Determine the mass of hydrochloric acid:
m (HCl) = m (Mg) * (2 * M (HCl)) / M (Mg) = 9.6 * 2 * 36.5 / 24 = 29.2 g.
Determine the amount of hydrochloric acid substance:
ν (HCl) = m (HCl) / M (HCl) = 29.2 / 36.5 = 0.8 mol.
From the reaction equation:
ν (Mg) = ν (H2).
m (Mg) / M (Mg) = ν (H2).
ν (H2) = 9.8 / 24 = 0.4 mol.
ν (H2) = m / M, hence m = 0.4 * 2 = 0.8 g.
Answer: You need 0.8 mol of acid to form 0.4 mol of hydrogen, or 29.2 g to get 0.8 g of hydrogen.