Final answer:
To find the grams of nitrogen in ammonium nitrate, calculate the mass percentage of nitrogen and apply it to the sample's mass. The mass of nitrogen in a 139.3 g sample is approximately 48.76 g.
Step-by-step explanation:
To calculate the grams of nitrogen in a 139.3 g sample of ammonium nitrate (NH4NO3), we need to determine the mass percentage of nitrogen in the compound and apply it to the total mass.
Ammonium nitrate contains two nitrogen atoms per formula unit. The molar mass of NH4NO3 is 14.01 (N) x 2 + 4.02 (H) x 4 + 16.00 (O) x 3 = 80.06 g/mol. The total mass of nitrogen per mole of NH4NO3 is 14.01 x 2 = 28.02 g/mol.
The mass percentage of nitrogen is (28.02 g/mol nitrogen) / (80.06 g/mol NH4NO3) x 100, which is approximately 35%. Therefore, in the 139.3 g sample of ammonium nitrate, the mass of nitrogen is 139.3 g x 0.35 = 48.755 g of nitrogen, rounded to two decimal places is 48.76 g.