Redox Titration.chem 12: What is the number of moles...?

A chemist who wishes to yze a sample of hydrated copper (ii) nitrate finds that when a sample with m 1.08g is dissolved in water and excess KI solution added, 34.9ml of 0.128M Na2S2O3 is required to react with the liberated iodine.What is the number of moles of water per mole of copper(ii) nitrate in the hydrated crystal?