# What Is the Percentage of Aluminum in Aluminum Oxide Al2o3?

The percentage of aluminum in aluminum oxide is 52.93 percent. To find this percentage, it is necessary to know the atomic masses of aluminum and oxygen and the molecular formula Al2O3, which provides the number of atoms of aluminum and oxygen in aluminum oxide.

From the formula, the number of aluminum atoms is two and the number of oxygen atoms is three. Using the periodic table, a student can find the atomic masses of aluminum as 26.9815386 grams per mole and oxygen as 16.9994 grams per mole. Multiplying the number of atoms of each of these elements by its respective atomic weight and then adding them, the molecular weight of Al2O3 is 101.961276 grams per mole.

The next step is to divide the molar mass of aluminum in the formula by the molar mass of Al2O3, or (2 x 26.9815386)/101.961276. This gives the result 0.5292507. To find the percentage of aluminum, multiply 0.5292507 by 100 percent to get 52.93 percent when rounded to the hundredth place.