A mixture weighing 10 g, consisting of powders of zinc and zinc oxide, was treated with an excess

A mixture weighing 10 g, consisting of powders of zinc and zinc oxide, was treated with an excess of hydrochloric acid. As a result of the reaction, a gas with a volume of 2.24 liters was released. Calculate the mass fraction of zinc in the mixture.

The reaction is described by the following chemical equation:

Zn + 2HCl = ZnCl2 + H2;

Let’s calculate the chemical amount of hydrogen. For this purpose, we divide the volume of gas by the volume of 1 mole of gas (22.4 liters).

N H2 = 2.24 / 22.4 = 0.1 mol;

To obtain such an amount of hydrogen, it is necessary to dissolve 0.1 mol of zinc.

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

m Zn = 0.1 x 65 = 6.5 grams;

The mass fraction of zinc will be:

K = 6.5 / 10 = 0.65 = 65%;