Question

How many kilograms of ammonium nitrate are required to provide 2.50 kg of nitrogen into the soil?

A. 11.8 kg

B. 5.89 kg

C. 7.14 kg

D. 14.3 kg

Answer 1

Molecular formula of ammonium nitrate = NH₄NO₃

Molecular weight of NH₄NO₃ = 80 g/mol

Mass of Nitrogen = 2.50 kg

Number of moles of nitrogen = mass/at.wt. = 2.50 kg/(14 g/mol) = 0.178571 kmol

2 moles of N present in 1 mole of NH₄NO₃

So, 0.178571 kmol of N would be present in 0.178571 kmol * 1mol/2 mol = 0.089286 kmol of NH₄NO₃

Number of moles of NH₄NO₃ required = 0.089286 kmol

Mass of NH₄NO₃ = moles * mol.wt. = 0.089286 kmol * 80.04 g/mol = 7.142857 kg = 7.14 kg

Option C is the right answer.