Answer:
FeCl₃ . 6H₂O, BRAINLIST PLZ
Explanation:
1) The chemical formula of iron(III) chloride is FeCl₃ (the oxidation number of Fe is 3+, and the oxidation number of Cl is 1-).
2) The formula that you are lookin for the hydrate is of the type FeCl₃ . n H₂O, where n is the number of water molecules per each unit formula of Fe₂O₃.
3) Find the mass of anhydrous FeCl₃ by difference:
mass of FeCl₃ = mass of the sample - mass of the water in the sample
mass of FeCl₃ = 5.49g - 2.20 g = 3.29 g
4) Convert the mass of FeCl₃ in number of moles
number of moles = mass in grams / molar mass
molar mass of FeCl₃ = 55.845 g/mol + 3×35.453 g/mol = 162.204 g/mol
number of moles = 3.29 g / 162.204 g/mol = 0.0203 mol FeCl₃
5) Convert the mass of water in number of moles:
molar mass of water = 18.015 g/mol
number of moles of water = mass in grams / molar mass = 2.20 g / 18.015 g/mol = 0.122 moles H₂O
6) Find the mole ratio of water to iron chloride:
0.122 mol water / 0.0203 mol iron chloride = 6.01 ≈ 6
Therefore, the complete formula of the hydrate is FeCl₃ . 6H₂O,
