60. Solving a chemistry problem

3. A portion of 1.6160 g of technical (NH4)2SO4 for determining the content of NH3 in it is dissolved in a volumetric flask with a capacity of 250 cm3. When boiling 25.00 cm3 of the resulting solution with a concentrated NaOH solution, the evolved ammonia is absorbed by the titrated solution of H2SO4. The excess sulfuric acid was titrated with NaOH. Calculate the percentage of ammonia in (NH4)2SO4 if 40.00 cm3 0.1020 N was taken to absorb NH3. H2SO4 solution, and 17.00 cm3 0.09690 N was used for back titration. NaOH solution.