posted by rose on .
A 2.50g sample of a hydrate of calcium nitrate was heated, and only 1.70g of the anhydrous salt remained. what is the formula of the hydrate?
Ca(NO3)2.xH2O ==> Ca(NO3)2 + xH2O
mols Ca(NO3)2 = 1.70/164 = about 0.0104
mols H2O = 0.044
0.0444/0.0104 = 4.3. Usually these come out closer to whole numbers than this. Check the figures.