Question

Write the name of the following compound and deduce its molecular mass.

AlPO₄

Answer 1

AlPO₄ - Aluminium phosphate

Molecule	Constituent elements	Atomic mass u	Number of atoms in the molecule	Atomic mass × number of atoms	Mass of the Constituents u
AlPO4	Al	27	1	27 × 1	27
	P	31	1	31 × 1	31
	O	16	4	16 × 4	64

The molecular mass of AlPO₄ = Sum of Constituent atomic masses

(Molecular mass of AlPO₄) = (Atomic mass of Al) × 1 + (Atomic mass of P) × 1 + (Atomic mass of O) × 4

= (27 × 1) + (31 × 1) + (16 × 4)

= 27 + 31 + 64

= 122 u