Determine the mass of hydrogen, which is released upon dissolution of 0.65 g of zinc in an excess of hydrochloric acid.

The laboratory method for producing hydrogen consists in dissolving zinc in hydrochloric acid.

Zn + 2HCl → ZnCl2 + H2;

The amounts of zinc dissolved and hydrogen produced will be equivalent.

Find the molar amount of zinc.

M Zn = 65 grams / mol;

N Zn = 0.65 / 65 = 0.01 mol;

Let’s calculate the weight of 0.01 mol of hydrogen. For this purpose, we multiply the chemical amount of the gas by its molar weight.

M H2 = 2 grams / mol;

m H2 = 2 x 0.01 = 0.02 grams;