Question

0.2313g of an organic substance gave 40ml of moist nitrogen measured at 15°C and 745mm pressure. Calculate the % of nitrogen. (aq. tension at 15°C is 12.7mm)​

Answer 1

The percentage of nitrogen is 19.36 %

Explanation:

As we know that:

P1 V1 / T1 = P2V2 / T2

P1 = P (moist) - aqueous tension = 732.7 - 12.7

P1 = 720 mmg

Now

720 x 40 / 288.15 K = 760 x V2 / 273

V2 = 99.94 x 273 / 760

V2 = 35.89 ml

Now

22400 ml nitrogen has mass = 28 g

35.89 ml has mass = 28 / 22400 x 35.89 = 0.0448 g

% of nitrogen = wt of nitrogen / wt of O.C x 100

% of nitrogen = 0.0448 / 0.2313 x 100

% of nitrogen = 19.36 %

Thus the percentage of nitrogen is 19.36 %