16. If all the N in 10.0 mmols urea, CO(NH2)2, is converted to NH4HSO4, and if with excess NaOH the NH3 is evolved and caught in 50.0 mL of HCl (1.00 mL ≈ 0.03000 g CaCO3), what volume of NaOH (1.00 mL ≈ 0.3465 g H2C2O4.2H2O) would be required for complete titration?

17. The percentage of protein in meat products is determined by multiplying the %N as determined by the kjeldahl method by the arbitrary factor 6.25. A sample of processed meat scrap weighing 2.000 g is digested with concd H2SO4 and Hg (catalyst) until the N present has been converted to NH4HSO4. This is treated with excess NaOH, and the liberated NH3 is caught in 50.0 mL pipetful H2SO4 (1.000 mL ≈ 0.01860 g Na2O). The excess acid requires 28.80 mL NaOH (1.000 mL ≈ 0.1266 g KHP). Calculate % protein in the meat scrap.

18. A 2.00 g sample of steel is burned in O2, and the evolved CO2 after passing through appropriate purifying trains is caught in 100 mL Ba(OH)2 solution. The supernatant liquid requires 75.0 mL HCl (1.00 mL ≈ 0.00626 g Na2CO3 , 1.00 mL ≈ 1.12 ml Ba(OH)2 ). What is the % Carbon in the steel?

19. A sample of limestone is titrated for its value as a neutralizing agent. A sample weighing 1.000 g is taken. What must be the normality of the titrating acid so that every 10 ml will represent 4 ½ % of the neutralizing value expressed in terms of percentage of CaO.

20. What weight of soda ash must be taken for analysis so that by using 0.5000N HCl for titrating, (a) buret reading will equal the percentage of Na2O, (b) three times the buret reading will equal the percentage of Na2O, (c) every 3 mL will represent 1% Na2O (d) each mL will represent 3% Na2O (e) the buret reading and the percentage of Na2O will be in the respective ratio 2:3?