How do you work out the mass of water of crystallisation for 13.5 g of
The correct answer is 3.24 g of water but I'm unable to derive the answer.
What I have tried:
I worked out the mols of aluminium sulfate which is approx 0.038 mol by dividing 13.5 g/353.5.
Since the ratio of aluminium sulfate: water of crystallisation is 1:6, I multiplied the number of mols by 6 to result in 0.228 mol of water.
To work out the mass, I multiplied mols of water by molar mass to result in 4.101 g which is NOT the answer of 3.24 g .
What am I doing wrong and what is the correct method?