how do you get the gram formula mass of Ca3(PO4)2?

Question

explain please :)

Answer 1

Ca3(PO4)2

Ca = 40.0 x 3 = 120.0
P = 31.0 x 2 = 62.0
O = 16.0 x 8 = 128.0
total = 310.0 amu or grams

Look up the mass of each element on the periodic table. Multiply the mass by the number of atoms of that element - this is given by the subscripts. The total is the formula mass.