Magnesium + Nitrogen

Magnesium + Nitrogen ➜ Magnesium Nitride
3Mg + N₂ ➜ Mg₃N₂
3Mg = 2•24.3 = 72.9 g/mol
N₂ = 28 g/mol
Mg₃N₂ = 3•24.3+2•14 = 100.9 g/mol

72.9 g of Mg react with 28 g of N₂ ➜ 100.9 g of Mg₃N₂