The amount of nitrogen in an organic substance can be determined by an analytical method called the Kjeldahl method, in which all the nitrogen in the organic substance is converted to ammonia. The ammonia, which is a weak base, can be neutralized with hydrochloric acid, as described by the equation NH, (19) + HCl(aq) NH Cl(aq) If 70.0 mL of 0.150 M HCl(aq) is needed to neutralize all the NH (g) from a 2.25 g sample of organic material calculate the mass percentage of nitrogen in the sample. mass percentage: A 0.450 g sample of impure CaCO3(s) is dissolved in 50,0 mL of 0.150 M HCl(aq). The equation for the reaction is CaCO,(s) + 2 HCl(aq) CaCl(aq) + H2O(1) + CO2(g) The excess HCl(aq) is titrated by 5.05 mL of 0.125 M NaOH(aq). Calculate the mass percentage of CaCO,(s) in the sample. mass percentage: Question Source MRG-General Che