What volume of hydrogen is formed by the interaction of 240 mg of magnesium containing 10% impurities

What volume of hydrogen is formed by the interaction of 240 mg of magnesium containing 10% impurities with hydrochloric acid? Calculate the amount of gas substance.

Let’s compose the reaction equation: Mg + 2HCl = MgCl2 + H2;

Given: m (Mg) = 240 g; mass fraction (Mg) = 90%.

Find: V (H2) =?; amount of substance =?.

Solution:

1) The mass of reacted magnesium is 240 * 0.9 = 216 g.

2) Amount of substance (Mg) = 216 g / 24 g / mol = 0.009 mol.

3) Amount of substance (Mg): (H2) = 1: 1 = 0.009 mol.

4) V (H2) = 0.009 mol * 22.4 L / mol = 0.2016 L.