A mixture of Zn3(PO4)2 and its hydrate Zn3(PO4)2•4H2O has a mass of 1.9497 g. After heating to drive
off all the water, the mass is only 1.8311 g. What is the weight percentage of Zn3(PO4)2•4H2O in the original
mixture? Report your answer to 4 significant figures.
Molar masses: Zn3(PO4)2 386.11 g/mol; Zn3(PO4)2•4H2O 458.17 g/mol.
Here is my work...
1.9497g - 1.8311g = 0.1186g
(386.11/72.06) x 0.1186 g = 0.635479406
0.1186g + 0.635479406g = 0.7541g
0.7541g * 100% = 75.41 %
Is this the correct technique?