Answer:
Mg is the limiting reactant
The theoretical yield is 105.2 g of Mg3N2
Explanation:
3Mg(s) + N2(g) -----> Mg3N2(s)
Number of moles of Mg = 75g/24g/mol = 3.125 moles
3 moles of Mg yields 1 mole of Mg3N2
3.125 moles of Mg yields 3.125 × 1/3 = 1.042 moles of Mg3N2
Number of moles of N2 = 45g/28g/mol = 1.607 moles
1 mole of N2 yields 1 mole of Mg3N2
1.607 moles of N2 yields 1.607 moles Mg3N2
Hence, Mg is the limiting reactant
The theoretical yield of Mg3N2 = 1.042 moles of Mg3N2 × 101 g/mol = 105.2 g of Mg3N2