The amount of nitrogen in an organic substance can be determined by an analytica

Question

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 ammoinia. The ammoinia, which is a weak base, can be neutralized with hydrochloric acid , as described by the equation

NH3 (aq) + HCl (aq) ---> NH4Cl (aq)

If 80.0 mL of 0.150 M HCl  (aq) is needed to neutralize all the NH3(g) from a 2.25G sample of organic material.

Calculate the mass percentage of nitrogen in the sample.

Explanation / Answer

moles of HCl = moles of NH3 = molarity * vol = 0.15*80/1000 = 0.012

0.012moles of ammonia formed = 0.012moles = 0.012*17 = 0.204g

So ammonia formed from 2.25g of sample = 0.204g

So mass % of N = 0.204*100/2.25 = 9.06%

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.