The molar mass of aluminium sulfate is 342.2 g/mol.
Aluminium sulfate is an with the formula ##Al_2(SO_4)_3##.
It is formed when 2 aluminium cations, ##Al^(3+)##, bond to 3 sulfate anions, ##SO_4^(2-)##.
To get the molar mass of the compound you need to add the molar masses of all the atoms that form the aluminium sulfate formula unit.
This means that you have
- two atoms of aluminium – ##2 * “27.0 g/mol”##
- three atom of sulfur – ##3 * “32.07 g/mol”##
- twelve atoms of oxygen – ##12 * “16.0 g/mol”##
The molar mass of the compound will thus be
##M_M = color(green)(“342.2 g/mol”)##
