Determine the molecular weight of iron (III) bromide hexahydrate, a substance used as a catalyst in organic reactions.Group of answer choices313.57 amu403.65 amu355.54 amu317.61 amu

To determine the molecular weight of iron (III) bromide hexahydrate, we need to add up the atomic weights of all the atoms in the formula. The formula for iron (III) bromide hexahydrate is FeBr3•6H2O.

1. Iron (Fe) has an atomic weight of 55.85 amu.
2. Bromine (Br) has an atomic weight of 79.90 amu, and there are three bromine atoms in the formula, so we multiply 79.90 by 3 to get 239.7 amu.
3. For the water (H2O) part, hydrogen (H) has an atomic weight of 1.01 amu, and there are two hydrogen atoms in each water molecule, so we multiply 1.01 by 2 to get 2.02 amu. Oxygen (O) has an atomic weight of 16.00 amu. So, the total weight for one water molecule is 2.02 + 16.00 = 18.02 amu. Since there are six water molecules in the formula, we multiply 18.02 by 6 to get 108.12 amu.

Finally, we add up the atomic weights of iron, bromine, and water to get the molecular weight of iron (III) bromide hexahydrate:

55.85 (Fe) + 239.7 (Br3) + 108.12 (6H2O) = 403.67 amu

So, the closest answer to the molecular weight of iron (III) bromide hexahydrate is 403.65 amu.