A mixture of CaCO3 and (NH4)2CO3 is 60.1% CO3 by mass. Find the mass percent of CaCO3 in the mixture?

Answer 1

For pure CaCO3 (100.087 g/mol), it contains 40.078/100.087 = 40.043% Ca and 60.009/100.087 = 59.957% CO3.
For pure (NH4)2CO3 (96.086 g/mol), it contains 36.077/96.086 = 37.547% NH4 and 60.009/96.086 = 62.453% CO3.
Suppose the mass percent of CaCO3 in the mixture is X, we have:
59.957%X + 62.453%(1 - X) = 60.1%
Solve for X, we get: X = 94.3%
That is to say, the mass percent of CaCO3 in the mixture is 94.3%.