chem 1 question about mass percent?

Question

A student completes two trials of an experiment and calculates the mass percent magnesium in the product as 62.39%. Assuming that the product is a mixture of MgO and Mg3N2, calculate the mass percent of MgO in the synthesized product. (Hint: calculate the theoretical percent magnesium for comparison in both the MgO and Mg3N2.)

Answer 1

The mass percent of Mg in MgO is: 24.305/(24.305 + 15.999) = 0.60304.
The mass percent of Mg in Mg3N2 is: 3x24.305/(3x24.305 + 2x14.007) = 0.72244.
Let the mass percent of MgO in the synthesized product to be X:
0.60304X + 0.72244(1 - X) = 0.6239
X = 82.53%
The mass percent of MgO in the synthesized product is 82.53%.