Zinc was treated with a 50 cm3 solution (density = 1.1 g / cm3) with a mass fraction of hydrogen

Zinc was treated with a 50 cm3 solution (density = 1.1 g / cm3) with a mass fraction of hydrogen chloride of 20%. Determine the mass of zinc reacted and the volume of gas evolved.

When dissolved in hydrochloric acid, metallic zinc is converted to zinc chloride.

Zn + 2HCl = ZnCl2 + H2;

Let’s determine the chemical amount of hydrogen chloride. To do this, we divide its weight by the mass of 1 mole of acid.

M HCl = 1 + 35.5 = 36.5 grams / mol;

N HCl = 50 x 1.1 x 0.2 / 36.5 = 0.3 mol;

With this amount of acid, 0.3 / 2 = 0.15 mol of zinc will react.

Let’s calculate the weight of zinc. To do this, multiply its amount by the weight of 1 mole of this metal.

N Zn = 0.15 x 65 = 9.75 grams;

This will synthesize 0.15 mol of hydrogen. Let’s find its volume. To do this, multiply the amount of substance by the volume of 1 mole of gas (22.4 liters).

V H2 = 0.15 x 22.4 = 3.36 liters;