Calculate the mass of alumina that is formed by the complete combustion of pure aluminum

Calculate the mass of alumina that is formed by the complete combustion of pure aluminum with a mass of 4.05 grams in a stream of oxygen.

Elemental aluminum reacts with oxygen gas to form alumina. The reaction is described by the following chemical reaction equation:

4Al + 3O2 = 2Al2O3;

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

M Al = 27 grams / mol;

N Al = 4.05 / 27 = 0.15 mol;

When oxidizing this amount of aluminum, 2 times less amount of aluminum oxide will be obtained. Let’s calculate its mass.

To do this, multiply the amount of the resulting substance by its molar weight.

M Al2O3 = 27 x 2 + 16 x 3 = 102 grams / mol;

N Al2O3 = 0.15 / 2 = 0.075 mol;

m Al2O3 = 0.075 x 102 = 7.555 grams;