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 nh3(aq)+hcl(aq)⟶nh4cl(aq) nh3(aq)+hcl(aq)⟶nh4cl(aq) if 88.0 ml88.0 ml of 0.150 m hcl(aq)0.150 m hcl(aq) is needed to neutralize all the nh3(g)nh3(g) from a 2.25 g sample of organic material, calculate the mass percentage of nitrogen in the sample.

The mass percent of nitrogen in the sample is 8.2 %

Explanation:

Kjeldahl method is defined as the analytical method which is used in the determination of nitrogen content in any organic compound.

In this method, nitrogen is converted into ammonia and the ammonia formed is then reacted with an acid.

The chemical equation for the reaction of ammonia with hydrochloric acid follows:

To calculate the percentage of nitrogen in the organic compound, we use the equation:

where,

= molarity of acid used = 0.150 M

= Volume of acid used (in mL) = 88.0 mL

w = mass of sample = 2.25 g

Putting values in above equation, we get:

Hence, the mass percent of nitrogen in the sample is 8.2 %

when the volume of gas is   changed from   717.73 ml   to 852 ml   the temperature will   change   from 315   c to 452   c

    calculation

this is calculated using the charles law formula

that is,   v1/t1 = v2/t2

          v1=?

        t1 = 315 c   into   kelvin = 315 +273 = 588 k

        v2 = 852   ml

        t2 = 425c + 273 =698 k

make v1   the subject of the formula ( by   multiplying both side by t1)

  v1=( v2 xt1) / t2

v1= (852 ml   x 588 k)/ 698 k= 717.73 ml