What is the mass fraction of each chemical element in this substance Ca3 (PO4) 2?

To find the mass fraction of an element in a compound, it is necessary to divide the sum of the masses of all atoms of this element by the molar mass of the compound. Let’s calculate the molar mass of calcium phosphate:

M (Ca3 (PO4) 2) = 3 * 40 + 2 * (31 + (16 * 4)) = 310 g / mol.

Let’s find the mass fractions of each of the elements:

w (Ca) = (3 * 40) / 310 = 120/310 = 0.387

w (P) = (2 * 31) / 310 = 62/310 = 0.2

w (O) = (8 * 16) / 310 = 128/310 = 0.413

Answer: mass fraction of calcium = 0.387; mass fraction of phosphorus = 0.2; mass fraction of oxygen = 0.413.