What is the Molar mass of Fe2 (SO4) 3

399.88

Explanation:

The molar mass is just the number of total mass of each atom of each element.

2 - Fe = (55.845 x 2) = 111.69

3 - S = (32.06 x 3) = 96.18

12 - O = (15.999 x 12) = 191.988

For oxygen, it's being added 12 times because there is 4 in the compound times the 3 on the outside.

Now, add all of them and you have your answer!