12. Solving a chemistry problem

1. To determine nitrogen in flour, a sample of 0.8880 g was treated with concentrated sulfuric acid. converting nitrogen into ammonium salt (NH4HSO4). Ammonia was distilled from the salt by the action of alkali into a solution containing 20.0 cm3 HCl (THCl/NH3=0.0030 g/cm3), and the excess acid was titrated with 5.5 cm3 NaOH solution with С1/z=0.1962 mol/dm3. Calculate the percentage of nitrogen in the flour.