Determine the mass fraction of the element in the formula H3PO4.

Phosphoric acid has the following chemical formula H3PO4;

Its molecule consists of 1 phosphorus atom, 3 hydrogen atoms, 4 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 masses of the atoms of these elements to the molar mass of the molecule.

M 3H = 3 grams / mol;

M P = 31 grams / mol;

M 4O = 4 x 16 = 64 grams / mol;

M H3PO4 = 3 + 31 + 64 = 98 grams / mol;

The weight fraction of the elements will be:

K H = 3/98 = 0.031 = 3.1%;

K P = 31/98 = 0.316 = 31.6%;

K O = 64/98 = 0.653 = 65.3%;

Checking 3.1 + 31.6 + 65.3 = 100%;