What is the molar weight of FeSO4 * 7H2O?

To calculate the molar mass of a substance, you need to add the mass of each atom into a compound, taking into account indices or stoichiometric coefficients. Let’s calculate the mass of aqueous ferrous sulfate.

FeSO4 * 7H2O

M (Fe) = 56 g / mol

M (S) = 32 g / mol

M (O) = 16 g / mol. Taking into account the index “4”: 16 * 4 = 64.

M (H) = 1 g / mol. Taking into account the index “2”: 1 * 2 = 2.

Then M (FeSO4) = 152 g / mol.

M (H2O) = 18 g / mol. Given “7”: 7 * 18 = 126.

M (FeSO4 * 7H2O) = 126 + 152 = 278 g / mol