Determine the mass fraction of iron in Fe (OH) 3

Iron hydroxide has the following chemical formula Fe (OH) 3;

Its molecule consists of 1 iron atom, 3 hydrogen atoms, 3 oxygen atoms.

In order to calculate the mass fraction of the elements included in the molecule, it is necessary to find the ratio of the molar weights of the atoms of these elements to the molar weight of the molecule.

M Fe = 56 grams / mol;

M Fe (OH) 3 = 56 + 16 x 3 + 3 = 107 grams / mol;

The mass fraction of iron will be:

K Fe = 56/107 = 0.523 = 52.3%;