Answer:
The answer to your question is 47.44 g of Oxygen
Explanation:
Data
mass of Ammonia = 14.4 g
mass of Oxygen = ?
Balanced chemical reaction
         4NH₃  +  7O₂  ⇒  4NO₂  +  6H₂O
Process
1.- Calculate the molar mass of Ammonia
NH₃ = 4[(1 x 14) + (3 x 1)] = 4[14 + 3] = 4[17] = 68 g
2.- Calculate the molar mass of Oxygen
Oâ‚‚ = 7[16 x 2] = 7[32] = 224 g
3.- Use proportions to calculate the mass of Oxygen
           68g of NH₃ --------------------- 224 g of O₂
           14.4 g of NH₃ -----------------  x
            x = (14.4 x 224) / 68
            x = 3225.6/ 68
            x = 47.44 g