Question

Calculate the formula mass of Al2(SO4)3

Answer 1

First, take out your periodic table.

In Al2(SO4)3

there are three elements:

Al, S, O

•    2 atoms of aluminum
•    1x3=3 atoms of sulfur

•    4x3=12 atoms of oxygen

I will use the more efficient way.

2 Al = 2x27 =54 g/mole

3 S = 3x32 =96 g/mole

12O =12x16=192 g/mole

Formula mass or Molar mass of Al2(SO4)3

= 54 g/mole + 96 g/mole + 192 g/mole

= 342 g/mole

Hope it helps .