40 grams of technical zinc, containing 25% impurities, reacted with hydrochloric acid. find the volume of gas evolved

First, we determine the mass of zinc without impurities.

m = 40 * 0.75 = 30 g.

Let’s compose the reaction equation.

Zn + 2HCl = ZnCl2 + H2.

Determine the amount of zinc.

M (Zn) = 65 g / mol.

n = m / M.

n = 30/65 = 0.46 mol.

Let’s determine the amount of hydrogen substance.

0.46 mol zinc – x mol hydrogen.

1 mole of zinc – 1 mole of hydrogen.

X = 1 * 0.46: 1 = 0.46 mol.

Next, let’s determine the volume of hydrogen.

n = V / Vm.

Where n is the amount of substance.

m is the mass of the substance.

M is the molar mass of the substance.

V = n * Vm = 0.46 * 22.4 = 10.33 liters.

Answer: the volume of hydrogen is 10.33 liters.