Aluminium (Al) :2 atomes × 26,98 g/mol =53,96 g/mol
Soufre (S) :3 atomes × 32,06 g/mol =96,18 g/mol
Oxygène (O) :12 atomes × 16,00 g/mol =192,00 g/mol
Masse molaire de Al2(SO4)3 =53,96 g/mol (2) + 96,18 g/mol (3) + 192,00 g/mol (12)
=107,92 g/mol + 288,54 g/mol + 1920,00 g/mol
=2306,46 g/mole
En arrondissant au gramme près, la masse molaire du sulfate d'aluminium est 2306 g/mol .