A 25 g sample of a hydrate of Ca(NO3)2 was heated, and only 1.7 g of the anhydrous salt remained. What hydrate of Ca(NO3)2 was tested?

1 answer

Water in the sample = 25 g - 1.7 = 23.3
mols salt = 1.7/164 = approx 0.0104
mol H2O = 23.3/18 = 1.29
Find the ratio:
0.0104/0.0104 = 1.00
1.29/0.0104 = 124
So the formula would be Ca(NO3)2*124H2O but I don't believe this. Better check your numbers.