Initial mass of sample mixture: 7.38g, mass of salicylic acid recovered, 1.76g; mass of CuSO4•5H2O recovered, 4.23g. The recovered CuSO4•5H2O was then heated for 20 minutes at 120°C. The mass of the new hydrate was 3.15g.(The molar mass of H2O = 18.015 g/mol, and the molar mass of CuSO4= 159.61g/mol)
Calculate the mass percent of copper(II) sulfate pentahydrate in the recovered sample.