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

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

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;