Calculate the mass of hydrogen gas that will be released if you dissolve 4.5 grams of aluminum in hydrochloric acid.

Aluminum reacts violently with hydrochloric acid. This forms an aluminum chloride salt and releases hydrogen gas. The interaction is described by the following chemical equation.

Al + 3HCl = AlCl3 + 3/2 H2;

Let’s find the chemical amount of aluminum. For this purpose, we divide its weight by the molar weight of the substance.

M Al = 27 grams / mol;

N Al = 4.5 / 27 = 0.1666 mol;

The chemical amount of released hydrogen will be: 0.1666 x 3/2 = 0.25 mol

Let’s calculate its mass.

To do this, multiply the chemical amount of a substance by the weight of 1 mole of gas.

M H2 = 2 grams / mol;

m H2 = 0.1666 x 2 = 0.333 grams;