A hydrate of zinc nitrate has the formula Zn(NO3)2 . xH2O. If the mass of 1 mol of anhydrous zinc nitrate is 63.67% of the mass of 1 mol of the hydrate, what is the value of x?

3 answers

So the %H2O = 100 - 63.67 = 36.33
a 100 g sample contains 64.67 g Zn(NO3)2 and 36.33 g H2O.
mols H2O = 36.33/18.015
mols Zn(NO3)2 = 63.67/molar mass zinc nitrate (don't include the water).
Find the ratio of mols H2O to 1 mol Zn(NO3)2. That will be x in the formula.

7.8

x=6