What is the molar mass of iron(II) chloride tetrahydrate? The error interval is +/- 2 g/mol.

Answer 1

Add the atomic masses of the atoms in FeCl2.4H2O.
I don't know the connection to the error interval with this question but +/- 2 g/mol sounds large to me.

Answer 2

Chemical Formula: FeCl₂ * H₂O

55.85 + 2(35.45) + 2(1.01) + 16.00 = 144.77 g/mol