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Saturday, May 30, 2015

Volumetric Analysis Problems, 4

Category: Chemical Engineering Math

"Published in Newark, California, USA"

A 758 mg sample of full cream milk was analyzed by the Kjeldahl method; 38.61 mL of 0.1078 M HCl were required to titrate the liberated ammonia. Calculate the % N in the sample.

Solution:

The given word problem is about volumetric analysis in which the titration of a sample and a solution is involved. By Kjeldahl method, we can analyze the amount of protein present in any organic samples.  

If liberated ammonia is titrated with HCl solution, then the chemical reaction is


The amount of liberated ammonia in a sample is




By gravimetric analysis, the amount of nitrogen present in a sample is



Therefore, the percent of nitrogen in a sample of full cream milk is