A 0.5843-g sample of a plant food preparation was analyzed for its N content by the Kjeldahl method, the liberated NH3 being collected in 50.00 mL of 0.1062 M HCl. The excess acid required an 11.89 mL back-titration with 0.0925 M NaOH. Express the results of this analysis in terms of:

(a) %N (FW 14.007 g/mol).
(b) %urea, H2NCONH2 (FW 60.06 g/mol).
(c) %(NH4)2SO4 (FW 132.141 g/mol).
(d) %(NH4)3PO4(FW 149.09 g/mol).