Hydrate forumla help

Question

54.2g of Indium Nitrate ws heated to remove the water of hydration, producing 46.0g of the anhydrate.

What is the formula of the hydrate?

Answer 1

The anhydrate is Indium Nitrate, but without the water attached.

Because we are only left with 46.0g of In(NO3)3, that means

54.2g-46.0g = 8.2g of water was evaporated.

We know that water (H2O) has a molar mass of ~18g/mol

Thus, 8.2/18 = 0.46mol H2O was evaporated = ~0.5mol

Thus, your formula (for the hydrate) should be In(NO3)3•(1/2)H2O

[Answer: see above]