The molar mass of Ca3(PO4)2 is 310.17 grams per mole. The molar mass of the compound is calculated by adding together the total mass of the calcium, phosphate and oxygen atoms.
The mass of each atom is based on the atomic weight of each element listed on the periodic table of elements. For example, the mass of one atom of calcium is 40.078 grams per mole. For the three atoms of calcium contained in the formula Ca3(PO4)2, the total mass of calcium is 120.234 grams per mole. The same method is used to determine a total mass of 61.947 grams per mole for the two atoms of phosphorous in a molecule of Ca3(PO4)2. As well finding a total mass of 127.9952 grams per mole for the eight atoms of oxygen.