What is the mass fraction of iron in iron oxide (3)?

Iron oxide (3) has the chemical formula Fe2O3.

It consists of two iron atoms and three oxygen atoms.

To find the mass fractions of these elements, it is necessary to find the ratio of their molar masses to the molar mass of the compound.

M Fe2O3 = 56 x 2 + 16 x 3 = 160 grams / mol;

M 2Fe = 56 x 2 = 112 grams / mol;

M 3O = 16 x 3 = 48 grams / mol;

Let us find the mass fractions of elements through the ratio of molar masses:

Iron:

K Fe = 112/160 = 70%

Oxygen:

K O = 48/160 = 30%

Check: 30 + 70 = 100%;